diff --git a/lisp/erc/erc-dcc.el b/lisp/erc/erc-dcc.el
index cfd17c9d479..b4d925f3224 100644
--- a/lisp/erc/erc-dcc.el
+++ b/lisp/erc/erc-dcc.el
@@ -420,7 +420,7 @@ where FOO is one of CLOSE, GET, SEND, LIST, CHAT, etc."
        'erc-cmd-DCC)))
 
 ;;;###autoload
-(defun pcomplete/erc-mode/DCC ()
+(pcomplete-define "erc-mode/DCC" ()
   "Provide completion for the /DCC command."
   (pcomplete-here (append '("chat" "close" "get" "list")
                           (when (fboundp 'make-network-process) '("send"))))
@@ -1142,9 +1142,9 @@ Possible values are: ask, auto, ignore."
                                      erc-dcc-send-request)))
       t)))
 
-(defun pcomplete/erc-mode/CREQ ()
+(pcomplete-define "erc-mode/CREQ" ()
   (pcomplete-here '("auto" "ask" "ignore")))
-(defalias 'pcomplete/erc-mode/SREQ #'pcomplete/erc-mode/CREQ)
+(pcomplete-define "erc-mode/SREQ" () (pcomplete/erc-mode/CREQ))
 
 (defvar erc-dcc-chat-filter-functions '(erc-dcc-chat-parse-output)
   "Abnormal hook run after parsing (and maybe inserting) a DCC message.
diff --git a/lisp/erc/erc-notify.el b/lisp/erc/erc-notify.el
index f194fbc6643..7115c4dd6ff 100644
--- a/lisp/erc/erc-notify.el
+++ b/lisp/erc/erc-notify.el
@@ -243,7 +243,7 @@ with args, toggle notify status of people."
                   (&optional postfix))
 
 ;;;###autoload
-(defun pcomplete/erc-mode/NOTIFY ()
+(pcomplete-define "erc-mode/NOTIFY" ()
   (require 'erc-pcomplete)
   (pcomplete-here (append erc-notify-list (pcomplete-erc-all-nicks))))
 
diff --git a/lisp/erc/erc-pcomplete.el b/lisp/erc/erc-pcomplete.el
index e5c72cda796..cbf86d0a997 100644
--- a/lisp/erc/erc-pcomplete.el
+++ b/lisp/erc/erc-pcomplete.el
@@ -103,7 +103,7 @@ for use on `completion-at-point-function'."
 
 ;;; Programmable completion logic
 
-(defun pcomplete/erc-mode/complete-command ()
+(pcomplete-define "erc-mode/complete-command" ()
   (pcomplete-here
    (append
     (pcomplete-erc-commands)
@@ -112,88 +112,88 @@ for use on `completion-at-point-function'."
 (defvar erc-pcomplete-ctcp-commands
   '("ACTION" "CLIENTINFO" "ECHO" "FINGER" "PING" "TIME" "USERINFO" "VERSION"))
 
-(defun pcomplete/erc-mode/CTCP ()
+(pcomplete-define "erc-mode/CTCP" ()
   (pcomplete-here (pcomplete-erc-nicks))
   (pcomplete-here erc-pcomplete-ctcp-commands))
 
-(defun pcomplete/erc-mode/CLEARTOPIC ()
+(pcomplete-define "erc-mode/CLEARTOPIC" ()
   (pcomplete-here (pcomplete-erc-channels)))
 
-(defun pcomplete/erc-mode/DEOP ()
+(pcomplete-define "erc-mode/DEOP" ()
   (while (pcomplete-here (pcomplete-erc-ops))))
 
-(defun pcomplete/erc-mode/DESCRIBE ()
+(pcomplete-define "erc-mode/DESCRIBE" ()
   (pcomplete-here (pcomplete-erc-nicks)))
 
-(defun pcomplete/erc-mode/IDLE ()
+(pcomplete-define "erc-mode/IDLE" ()
   (while (pcomplete-here (pcomplete-erc-nicks))))
 
-(defun pcomplete/erc-mode/KICK ()
+(pcomplete-define "erc-mode/KICK" ()
   (pcomplete-here (pcomplete-erc-channels))
   (pcomplete-here (pcomplete-erc-nicks)))
 
-(defun pcomplete/erc-mode/LOAD ()
+(pcomplete-define "erc-mode/LOAD" ()
   (pcomplete-here (pcomplete-entries)))
 
-(defun pcomplete/erc-mode/MODE ()
+(pcomplete-define "erc-mode/MODE" ()
   (pcomplete-here (pcomplete-erc-channels))
   (while (pcomplete-here (pcomplete-erc-nicks))))
 
-(defun pcomplete/erc-mode/ME ()
+(pcomplete-define "erc-mode/ME" ()
   (while (pcomplete-here (pcomplete-erc-nicks))))
 
-(defun pcomplete/erc-mode/SAY ()
+(pcomplete-define "erc-mode/SAY" ()
   (pcomplete-here (pcomplete-erc-nicks))
   (pcomplete-here (pcomplete-erc-nicks))
   (while (pcomplete-here (pcomplete-erc-nicks))))
 
-(defun pcomplete/erc-mode/MSG ()
+(pcomplete-define "erc-mode/MSG" ()
   (pcomplete-here (append (pcomplete-erc-all-nicks)
                           (pcomplete-erc-channels)))
   (while (pcomplete-here (pcomplete-erc-nicks))))
 
-(defun pcomplete/erc-mode/NAMES ()
+(pcomplete-define "erc-mode/NAMES" ()
   (while (pcomplete-here (pcomplete-erc-channels))))
 
-(defalias 'pcomplete/erc-mode/NOTICE #'pcomplete/erc-mode/MSG)
+(pcomplete-define "erc-mode/NOTICE" () (pcomplete/erc-mode/MSG))
 
-(defun pcomplete/erc-mode/OP ()
+(pcomplete-define "erc-mode/OP" ()
   (while (pcomplete-here (pcomplete-erc-not-ops))))
 
-(defun pcomplete/erc-mode/PART ()
+(pcomplete-define "erc-mode/PART" ()
   (pcomplete-here (pcomplete-erc-channels)))
 
-(defalias 'pcomplete/erc-mode/LEAVE #'pcomplete/erc-mode/PART)
+(pcomplete-define "erc-mode/LEAVE" () (pcomplete/erc-mode/PART))
 
-(defun pcomplete/erc-mode/QUERY ()
+(pcomplete-define "erc-mode/QUERY" ()
   (pcomplete-here (append (pcomplete-erc-all-nicks)
                           (pcomplete-erc-channels)))
   (while (pcomplete-here (pcomplete-erc-nicks)))
   )
 
-(defun pcomplete/erc-mode/SOUND ()
+(pcomplete-define "erc-mode/SOUND" ()
   (while (pcomplete-here (pcomplete-entries))))
 
-(defun pcomplete/erc-mode/TOPIC ()
+(pcomplete-define "erc-mode/TOPIC" ()
   (pcomplete-here (pcomplete-erc-channels)))
 
-(defun pcomplete/erc-mode/WHOIS ()
+(pcomplete-define "erc-mode/WHOIS" ()
   (while (pcomplete-here (pcomplete-erc-nicks))))
 
-(defun pcomplete/erc-mode/UNIGNORE ()
+(pcomplete-define "erc-mode/UNIGNORE" ()
   (pcomplete-here (erc-with-server-buffer erc-ignore-list)))
 
-(defun pcomplete/erc-mode/RECONNECT ()
+(pcomplete-define "erc-mode/RECONNECT" ()
   (pcomplete-here '("cancel"))
   (pcomplete-opt "a"))
 
-(defun pcomplete/erc-mode/BANLIST ()
+(pcomplete-define "erc-mode/BANLIST" ()
   (pcomplete-opt "f"))
-(defalias 'pcomplete/erc-mode/BL #'pcomplete/erc-mode/BANLIST)
+(pcomplete-define "erc-mode/BL" () (pcomplete/erc-mode/BANLIST))
 
-(defun pcomplete/erc-mode/MASSUNBAN ()
+(pcomplete-define "erc-mode/MASSUNBAN" ()
   (pcomplete-opt "f"))
-(defalias 'pcomplete/erc-mode/MUB #'pcomplete/erc-mode/MASSUNBAN)
+(pcomplete-define "erc-mode/MUB" () (pcomplete/erc-mode/MASSUNBAN))
 
 ;;; Functions that provide possible completions.
 
diff --git a/lisp/eshell/em-alias.el b/lisp/eshell/em-alias.el
index 2adbde98b28..34bcb736a91 100644
--- a/lisp/eshell/em-alias.el
+++ b/lisp/eshell/em-alias.el
@@ -182,7 +182,7 @@ file named by `eshell-aliases-file'.")
 (defvar pcomplete-stub)
 (autoload 'pcomplete-here "pcomplete")
 
-(defun pcomplete/eshell-mode/alias ()
+(pcomplete-define "eshell-mode/alias" ()
   "Completion function for Eshell's `alias' command."
   (pcomplete-here (eshell-alias-completions pcomplete-stub)))
 
diff --git a/lisp/eshell/em-basic.el b/lisp/eshell/em-basic.el
index 54394614711..b8165e71d3b 100644
--- a/lisp/eshell/em-basic.el
+++ b/lisp/eshell/em-basic.el
@@ -220,7 +220,7 @@ are:
      (dolist (kind eshell-debug-command)
        (eshell-printn (symbol-name kind))))))
 
-(defun pcomplete/eshell-mode/eshell-debug ()
+(pcomplete-define "eshell-mode/eshell-debug" ()
   "Completion for the `debug' command."
   (while (pcomplete-here '("error" "form" "process"))))
 
diff --git a/lisp/eshell/esh-var.el b/lisp/eshell/esh-var.el
index d79977a6dff..aa97dba1ffe 100644
--- a/lisp/eshell/esh-var.el
+++ b/lisp/eshell/esh-var.el
@@ -379,7 +379,7 @@ This function is explicit for adding to `eshell-parse-argument-hook'."
       (eshell-set-variable (match-string 1 set)
                            (match-string 2 set)))))
 
-(defun pcomplete/eshell-mode/export ()
+(pcomplete-define "eshell-mode/export" ()
   "Completion function for Eshell's `export'."
   (while (pcomplete-here
 	  (if eshell-complete-export-definition
@@ -393,7 +393,7 @@ the values of nil for each."
   (dolist (arg args)
     (eshell-set-variable arg nil)))
 
-(defun pcomplete/eshell-mode/unset ()
+(pcomplete-define "eshell-mode/unset" ()
   "Completion function for Eshell's `unset'."
   (while (pcomplete-here (eshell-envvar-names))))
 
@@ -405,7 +405,7 @@ the values of nil for each."
             args (cddr args)))
     last-value))
 
-(defun pcomplete/eshell-mode/set ()
+(pcomplete-define "eshell-mode/set" ()
   "Completion function for Eshell's `set'."
   (while (pcomplete-here (eshell-envvar-names))))
 
@@ -419,7 +419,7 @@ the values of nil for each."
 	      args (cddr args))))
     last-value))
 
-(defun pcomplete/eshell-mode/setq ()
+(pcomplete-define "eshell-mode/setq" ()
   "Completion function for Eshell's `setq'."
   (while (and (pcomplete-here (all-completions pcomplete-stub
 					       obarray #'boundp))
diff --git a/lisp/ldefs-boot.el b/lisp/ldefs-boot.el
index a54b3d60abc..bad22bf1ee8 100644
--- a/lisp/ldefs-boot.el
+++ b/lisp/ldefs-boot.el
@@ -25469,7 +25469,6 @@ for the result of evaluating EXP (first arg to `pcase').
 
 (autoload 'pcomplete/cd "pcmpl-unix"
 "Completion for `cd'.")
-(defalias 'pcomplete/pushd 'pcomplete/cd)
 (autoload 'pcomplete/rmdir "pcmpl-unix"
 "Completion for `rmdir'.")
 (autoload 'pcomplete/rm "pcmpl-unix"
@@ -25490,7 +25489,6 @@ for the result of evaluating EXP (first arg to `pcase').
 "Completion for the `od' command.")
 (autoload 'pcomplete/base32 "pcmpl-unix"
 "Completion for the `base32' and `base64' commands.")
-(defalias 'pcomplete/base64 'pcomplete/base32)
 (autoload 'pcomplete/basenc "pcmpl-unix"
 "Completion for the `basenc' command.")
 (autoload 'pcomplete/fmt "pcmpl-unix"
@@ -25517,11 +25515,6 @@ for the result of evaluating EXP (first arg to `pcase').
 "Completion for the `b2sum' command.")
 (autoload 'pcomplete/md5sum "pcmpl-unix"
 "Completion for checksum commands.")
-(defalias 'pcomplete/sha1sum 'pcomplete/md5sum)
-(defalias 'pcomplete/sha224sum 'pcomplete/md5sum)
-(defalias 'pcomplete/sha256sum 'pcomplete/md5sum)
-(defalias 'pcomplete/sha384sum 'pcomplete/md5sum)
-(defalias 'pcomplete/sha512sum 'pcomplete/md5sum)
 (autoload 'pcomplete/sort "pcmpl-unix"
 "Completion for the `sort' command.")
 (autoload 'pcomplete/shuf "pcmpl-unix"
@@ -25548,8 +25541,6 @@ for the result of evaluating EXP (first arg to `pcase').
 "Completion for the `unexpand' command.")
 (autoload 'pcomplete/ls "pcmpl-unix"
 "Completion for the `ls' command.")
-(defalias 'pcomplete/dir 'pcomplete/ls)
-(defalias 'pcomplete/vdir 'pcomplete/ls)
 (autoload 'pcomplete/cp "pcmpl-unix"
 "Completion for the `cp' command.")
 (autoload 'pcomplete/dd "pcmpl-unix"
@@ -25592,7 +25583,6 @@ for the result of evaluating EXP (first arg to `pcase').
 "Completion for the `echo' command.")
 (autoload 'pcomplete/test "pcmpl-unix"
 "Completion for the `test' command.")
-(defalias (intern "pcomplete/[") 'pcomplete/test)
 (autoload 'pcomplete/tee "pcmpl-unix"
 "Completion for the `tee' command.")
 (autoload 'pcomplete/basename "pcmpl-unix"
@@ -25643,7 +25633,6 @@ for the result of evaluating EXP (first arg to `pcase').
 "Completion for the `seq' command.")
 (autoload 'pcomplete/ssh "pcmpl-unix"
 "Completion rules for the `ssh' command.")
-(defalias 'pcomplete/rsh #'pcomplete/ssh)
 (autoload 'pcomplete/scp "pcmpl-unix"
 "Completion rules for the `scp' command.
 Includes files as well as host names followed by a colon.")
@@ -25659,12 +25648,8 @@ Includes files as well as host names followed by a colon.")
 
 (autoload 'pcomplete/tex "pcmpl-x"
 "Completion for the `tex' command.")
-(defalias 'pcomplete/pdftex 'pcomplete/tex)
-(defalias 'pcomplete/latex 'pcomplete/tex)
-(defalias 'pcomplete/pdflatex 'pcomplete/tex)
 (autoload 'pcomplete/luatex "pcmpl-x"
 "Completion for the `luatex' command.")
-(defalias 'pcomplete/lualatex 'pcomplete/luatex)
 (autoload 'pcomplete/tlmgr "pcmpl-x"
 "Completion for the `tlmgr' command.")
 (autoload 'pcomplete/rg "pcmpl-x"
@@ -25673,12 +25658,10 @@ Includes files as well as host names followed by a colon.")
 "Completion for the `ack' command.
 Start an argument with `-' to complete short options and `--' for
 long options.")
-(defalias 'pcomplete/ack-grep 'pcomplete/ack)
 (autoload 'pcomplete/ag "pcmpl-x"
 "Completion for the `ag' command.")
 (autoload 'pcomplete/bcc32 "pcmpl-x"
 "Completion function for Borland's C++ compiler.")
-(defalias 'pcomplete/bcc 'pcomplete/bcc32)
 (autoload 'pcomplete/rclone "pcmpl-x"
 "Completion for the `rclone' command.")
 (register-definition-prefixes "pcmpl-x" '("pcmpl-x-"))
diff --git a/lisp/org/org-pcomplete.el b/lisp/org/org-pcomplete.el
index f2b9798f91b..ac7316dac24 100644
--- a/lisp/org/org-pcomplete.el
+++ b/lisp/org/org-pcomplete.el
@@ -210,7 +210,7 @@ When completing for #+STARTUP, for example, this function returns
 
 ;;; Completion functions
 
-(defun pcomplete/org-mode/file-option ()
+(pcomplete-define "org-mode/file-option" ()
   "Complete against all valid file options."
   (require 'org-element)
   (pcomplete-here
@@ -237,51 +237,51 @@ When completing for #+STARTUP, for example, this function returns
 		    (org-get-export-keywords))))
    (substring pcomplete-stub 2)))
 
-(defun pcomplete/org-mode/file-option/author ()
+(pcomplete-define "org-mode/file-option/author" ()
   "Complete arguments for the #+AUTHOR file option."
   (pcomplete-here (list user-full-name)))
 
-(defun pcomplete/org-mode/file-option/date ()
+(pcomplete-define "org-mode/file-option/date" ()
   "Complete arguments for the #+DATE file option."
   (pcomplete-here (list (format-time-string (org-time-stamp-format)))))
 
-(defun pcomplete/org-mode/file-option/email ()
+(pcomplete-define "org-mode/file-option/email" ()
   "Complete arguments for the #+EMAIL file option."
   (pcomplete-here (list user-mail-address)))
 
-(defun pcomplete/org-mode/file-option/exclude_tags ()
+(pcomplete-define "org-mode/file-option/exclude_tags" ()
   "Complete arguments for the #+EXCLUDE_TAGS file option."
   (require 'ox)
   (pcomplete-here
    (and org-export-exclude-tags
 	(list (mapconcat #'identity org-export-exclude-tags " ")))))
 
-(defun pcomplete/org-mode/file-option/filetags ()
+(pcomplete-define "org-mode/file-option/filetags" ()
   "Complete arguments for the #+FILETAGS file option."
   (pcomplete-here (and org-file-tags (mapconcat #'identity org-file-tags " "))))
 
-(defun pcomplete/org-mode/file-option/language ()
+(pcomplete-define "org-mode/file-option/language" ()
   "Complete arguments for the #+LANGUAGE file option."
   (require 'ox)
   (pcomplete-here
    (pcomplete-uniquify-list
     (list org-export-default-language "en"))))
 
-(defun pcomplete/org-mode/file-option/priorities ()
+(pcomplete-define "org-mode/file-option/priorities" ()
   "Complete arguments for the #+PRIORITIES file option."
   (pcomplete-here (list (format "%c %c %c"
 				org-priority-highest
 				org-priority-lowest
 				org-priority-default))))
 
-(defun pcomplete/org-mode/file-option/select_tags ()
+(pcomplete-define "org-mode/file-option/select_tags" ()
   "Complete arguments for the #+SELECT_TAGS file option."
   (require 'ox)
   (pcomplete-here
    (and org-export-select-tags
 	(list (mapconcat #'identity org-export-select-tags " ")))))
 
-(defun pcomplete/org-mode/file-option/startup ()
+(pcomplete-define "org-mode/file-option/startup" ()
   "Complete arguments for the #+STARTUP file option."
   (while (pcomplete-here
 	  (let ((opts (pcomplete-uniquify-list
@@ -294,12 +294,12 @@ When completing for #+STARTUP, for example, this function returns
 		(setq opts (delete "showstars" opts)))))
 	    opts))))
 
-(defun pcomplete/org-mode/file-option/tags ()
+(pcomplete-define "org-mode/file-option/tags" ()
   "Complete arguments for the #+TAGS file option."
   (pcomplete-here
    (list (org-tag-alist-to-string org-current-tag-alist))))
 
-(defun pcomplete/org-mode/file-option/title ()
+(pcomplete-define "org-mode/file-option/title" ()
   "Complete arguments for the #+TITLE file option."
   (pcomplete-here
    (let ((visited-file (buffer-file-name (buffer-base-buffer))))
@@ -309,7 +309,7 @@ When completing for #+STARTUP, for example, this function returns
 	       (buffer-name (buffer-base-buffer)))))))
 
 
-(defun pcomplete/org-mode/file-option/options ()
+(pcomplete-define "org-mode/file-option/options" ()
   "Complete arguments for the #+OPTIONS file option."
   (while (pcomplete-here
 	  (pcomplete-uniquify-list
@@ -328,21 +328,21 @@ When completing for #+STARTUP, for example, this function returns
 		    (when item (push (concat item ":") items)))))
 	      items))))))
 
-(defun pcomplete/org-mode/file-option/infojs_opt ()
+(pcomplete-define "org-mode/file-option/infojs_opt" ()
   "Complete arguments for the #+INFOJS_OPT file option."
   (while (pcomplete-here
 	  (pcomplete-uniquify-list
 	   (mapcar (lambda (item) (format "%s:" (car item)))
 		   (bound-and-true-p org-html-infojs-opts-table))))))
 
-(defun pcomplete/org-mode/file-option/bind ()
+(pcomplete-define "org-mode/file-option/bind" ()
   "Complete arguments for the #+BIND file option, which are variable names."
   (let (vars)
     (mapatoms
      (lambda (a) (when (boundp a) (setq vars (cons (symbol-name a) vars)))))
     (pcomplete-here vars)))
 
-(defun pcomplete/org-mode/link ()
+(pcomplete-define "org-mode/link" ()
   "Complete against defined #+LINK patterns."
   (pcomplete-here
    (pcomplete-uniquify-list
@@ -351,7 +351,7 @@ When completing for #+STARTUP, for example, this function returns
 	     (append org-link-abbrev-alist-local
 		     org-link-abbrev-alist))))))
 
-(defun pcomplete/org-mode/tex ()
+(pcomplete-define "org-mode/tex" ()
   "Complete against TeX-style HTML entity names."
   (require 'org-entities)
   (while (pcomplete-here
@@ -359,11 +359,11 @@ When completing for #+STARTUP, for example, this function returns
 	   (remove nil (mapcar #'car-safe org-entities)))
 	  (substring pcomplete-stub 1))))
 
-(defun pcomplete/org-mode/todo ()
+(pcomplete-define "org-mode/todo" ()
   "Complete against known TODO keywords."
   (pcomplete-here (pcomplete-uniquify-list (copy-sequence org-todo-keywords-1))))
 
-(defun pcomplete/org-mode/searchhead ()
+(pcomplete-define "org-mode/searchhead" ()
   "Complete against all headings.
 This needs more work, to handle headings with lots of spaces in them."
   (while (pcomplete-here
@@ -376,7 +376,7 @@ This needs more work, to handle headings with lots of spaces in them."
 		(push (substring (org-link-heading-search-string) 1) tbl))
 	      (pcomplete-uniquify-list tbl))))))
 
-(defun pcomplete/org-mode/tag ()
+(pcomplete-define "org-mode/tag" ()
   "Complete a tag name.  Omit tags already set."
   (while (pcomplete-here
 	  (mapcar (lambda (x) (concat x ":"))
@@ -393,7 +393,7 @@ This needs more work, to handle headings with lots of spaces in them."
 	       (substring pcomplete-stub (match-end 0)))
 	  t)))
 
-(defun pcomplete/org-mode/drawer ()
+(pcomplete-define "org-mode/drawer" ()
   "Complete a drawer name, including \"PROPERTIES\"."
   (pcomplete-here
    (org-pcomplete-case-double
@@ -409,7 +409,7 @@ This needs more work, to handle headings with lots of spaces in them."
 	      (pcomplete-uniquify-list names))))
    (substring pcomplete-stub 1)))	;remove initial colon
 
-(defun pcomplete/org-mode/prop ()
+(pcomplete-define "org-mode/prop" ()
   "Complete a property name.  Omit properties already set."
   (pcomplete-here
    (org-pcomplete-case-double
@@ -422,7 +422,7 @@ This needs more work, to handle headings with lots of spaces in them."
 	      lst)))
    (substring pcomplete-stub 1)))
 
-(defun pcomplete/org-mode/block-option/src ()
+(pcomplete-define "org-mode/block-option/src" ()
   "Complete the arguments of a source block.
 Complete a language in the first field, the header arguments and
 switches."
@@ -445,7 +445,7 @@ switches."
 		     headers)
 		    '("-n" "-r" "-l"))))))
 
-(defun pcomplete/org-mode/block-option/clocktable ()
+(pcomplete-define "org-mode/block-option/clocktable" ()
   "Complete keywords in a clocktable line."
   (while (pcomplete-here '(":maxlevel" ":scope" ":lang"
 			   ":tstart" ":tend" ":block" ":step"
diff --git a/lisp/pcmpl-cvs.el b/lisp/pcmpl-cvs.el
index 21b8da68e40..925cf22b277 100644
--- a/lisp/pcmpl-cvs.el
+++ b/lisp/pcmpl-cvs.el
@@ -43,7 +43,7 @@
 ;; Functions:
 
 ;;;###autoload
-(defun pcomplete/cvs ()
+(pcomplete-define "cvs" ()
   "Completion rules for the `cvs' command."
   (let ((pcomplete-help "(cvs)Invoking CVS"))
     (pcomplete-opt "HQqrwlntvfab/T/e*d/z?s")
diff --git a/lisp/pcmpl-git.el b/lisp/pcmpl-git.el
index fc33b8bfa53..361f464a612 100644
--- a/lisp/pcmpl-git.el
+++ b/lisp/pcmpl-git.el
@@ -59,7 +59,7 @@ Files listed by `git ls-files ARGS' satisfy the predicate."
          (vc-git-revision-table nil))))
 
 ;;;###autoload
-(defun pcomplete/git ()
+(pcomplete-define "git" ()
   "Completion for the `git' command."
   (let ((subcommands (pcomplete-from-help `(,vc-git-program "help" "-a")
                                           :margin "^\\( +\\)[a-z]"
diff --git a/lisp/pcmpl-gnu.el b/lisp/pcmpl-gnu.el
index e25d686b9f0..ca089f30c39 100644
--- a/lisp/pcmpl-gnu.el
+++ b/lisp/pcmpl-gnu.el
@@ -48,7 +48,7 @@
 ;; Functions:
 
 ;;;###autoload
-(defun pcomplete/gzip ()
+(pcomplete-define "gzip" ()
   "Completion for `gzip'."
   (let ((pcomplete-help "(gzip)"))
     (pcomplete-opt "cdfhlLnNqrStvV123456789")
@@ -75,7 +75,7 @@
                  (and (not unzip-p) (not zipped)))))))))
 
 ;;;###autoload
-(defun pcomplete/bzip2 ()
+(pcomplete-define "bzip2" ()
   "Completion for `bzip2'."
   (pcomplete-opt "hdzkftcqvLVs123456789")
   (while (pcomplete-here
@@ -99,7 +99,7 @@
              (and (not unzip-p) (not zipped))))))))
 
 ;;;###autoload
-(defun pcomplete/make ()
+(pcomplete-define "make" ()
   "Completion for GNU `make'."
   (let ((pcomplete-help "(make)Top"))
     (pcomplete-opt "bmC/def(pcmpl-gnu-makefile-names)hiI/j?kl?no.pqrsStvwW.")
@@ -265,7 +265,7 @@ Return the new list."
     "--volno-file="))
 
 ;;;###autoload
-(defun pcomplete/tar ()
+(pcomplete-define "tar" ()
   "Completion for the GNU tar utility."
   ;; options that end in an equal sign will want further completion...
   (let (saw-option complete-within)
@@ -344,7 +344,7 @@ Return the new list."
 
 ;;;###autoload
 
-(defun pcomplete/find ()
+(pcomplete-define "find" ()
   "Completion for the GNU find utility."
   (let ((prec (pcomplete-arg 'last -1)))
     (cond ((and (pcomplete-match "^-" 'last)
@@ -379,7 +379,7 @@ Return the new list."
     (while (pcomplete-here (pcomplete-dirs) nil #'identity))))
 
 ;;;###autoload
-(defun pcomplete/awk ()
+(pcomplete-define "awk" ()
   "Completion for the `awk' command."
   (pcomplete-here-using-help "awk --help"
                              :margin "\t"
@@ -388,12 +388,12 @@ Return the new list."
                              :metavar "[=a-z]+"))
 
 ;;;###autoload
-(defun pcomplete/gpg ()
+(pcomplete-define "gpg" ()
   "Completion for the `gpg` command."
   (pcomplete-here-using-help "gpg --help" :narrow-end "^ -se"))
 
 ;;;###autoload
-(defun pcomplete/gdb ()
+(pcomplete-define "gdb" ()
   "Completion for the `gdb' command."
   (while
       (cond
@@ -406,12 +406,12 @@ Return the new list."
        (t (pcomplete-here (pcomplete-entries))))))
 
 ;;;###autoload
-(defun pcomplete/emacs ()
+(pcomplete-define "emacs" ()
   "Completion for the `emacs' command."
   (pcomplete-here-using-help "emacs --help" :margin "^\\(\\)-"))
 
 ;;;###autoload
-(defun pcomplete/emacsclient ()
+(pcomplete-define "emacsclient" ()
   "Completion for the `emacsclient' command."
   (pcomplete-here-using-help "emacsclient --help" :margin "^\\(\\)-"))
 
diff --git a/lisp/pcmpl-linux.el b/lisp/pcmpl-linux.el
index abf56260915..036f6b15a38 100644
--- a/lisp/pcmpl-linux.el
+++ b/lisp/pcmpl-linux.el
@@ -35,7 +35,7 @@
 ;; Functions:
 
 ;;;###autoload
-(defun pcomplete/kill ()
+(pcomplete-define "kill" ()
   "Completion for GNU/Linux `kill', using /proc filesystem."
   (if (pcomplete-match "^-\\(.*\\)" 0)
       (pcomplete-here
@@ -49,14 +49,14 @@
 	  nil #'identity)))
 
 ;;;###autoload
-(defun pcomplete/umount ()
+(pcomplete-define "umount" ()
   "Completion for GNU/Linux `umount'."
   (pcomplete-opt "hVafrnvt(pcmpl-linux-fs-types)")
   (while (pcomplete-here (pcmpl-linux-mounted-directories)
 			 nil #'identity)))
 
 ;;;###autoload
-(defun pcomplete/mount ()
+(pcomplete-define "mount" ()
   "Completion for GNU/Linux `mount'."
   (pcomplete-opt "hVanfFrsvwt(pcmpl-linux-fs-types)o?L?U?")
   (while (pcomplete-here (pcomplete-entries) nil #'identity)))
@@ -139,7 +139,7 @@ Test is done using `equal'."
       (nreverse result))))
 
 ;;;###autoload
-(defun pcomplete/systemctl ()
+(pcomplete-define "systemctl" ()
   "Completion for the `systemctl' command."
   (let ((subcmds (pcomplete-from-help
                   "systemctl --help"
@@ -171,7 +171,7 @@ Test is done using `equal'."
                     (pcomplete-entries)))))))))
 
 ;;;###autoload
-(defun pcomplete/journalctl ()
+(pcomplete-define "journalctl" ()
   "Completion for the `journalctl' command."
   (while (if (string-prefix-p "-" (pcomplete-arg 0))
              (pcomplete-here (pcomplete-from-help "journalctl --help"
diff --git a/lisp/pcmpl-rpm.el b/lisp/pcmpl-rpm.el
index b5858e6d3d1..4f3027c7394 100644
--- a/lisp/pcmpl-rpm.el
+++ b/lisp/pcmpl-rpm.el
@@ -102,7 +102,7 @@
   (pcomplete-dirs-or-entries "\\.rpm\\'"))
 
 ;;;###autoload
-(defun pcomplete/rpm ()
+(pcomplete-define "rpm" ()
   "Completion for the `rpm' command."
   ;; Originally taken from the output of `rpm --help' on a Red Hat 6.1 system.
   (let (mode)
@@ -390,7 +390,7 @@ STATUS should be one of --available or --installed."
                    status)))
 
 ;;;###autoload
-(defun pcomplete/dnf ()
+(pcomplete-define "dnf" ()
   "Completion for the `dnf' command."
   (let ((subcmds (pcomplete-from-help "dnf --help"
                                       :margin (rx bol (group (* " "))
diff --git a/lisp/pcmpl-unix.el b/lisp/pcmpl-unix.el
index 1c990a6b9c5..acf1069c89a 100644
--- a/lisp/pcmpl-unix.el
+++ b/lisp/pcmpl-unix.el
@@ -59,27 +59,27 @@ being via `pcmpl-ssh-known-hosts-file'."
 ;;; Shell builtins and core utilities
 
 ;;;###autoload
-(defun pcomplete/cd ()
+(pcomplete-define "cd" ()
   "Completion for `cd'."
   (while (pcomplete-here (pcomplete-dirs))))
 
 ;;;###autoload
-(defalias 'pcomplete/pushd 'pcomplete/cd)
+(pcomplete-alias "pushd" "cd")
 
 ;;;###autoload
-(defun pcomplete/rmdir ()
+(pcomplete-define "rmdir" ()
   "Completion for `rmdir'."
   (while (if (string-prefix-p "-" (pcomplete-arg))
              (pcomplete-here (pcomplete-from-help "rmdir --help"))
            (pcomplete-here (pcomplete-dirs)))))
 
 ;;;###autoload
-(defun pcomplete/rm ()
+(pcomplete-define "rm" ()
   "Completion for the `rm' command."
   (pcomplete-here-using-help "rm --help"))
 
 ;;;###autoload
-(defun pcomplete/xargs ()
+(pcomplete-define "xargs" ()
   "Completion for `xargs'."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "xargs --help"))
@@ -89,7 +89,7 @@ being via `pcmpl-ssh-known-hosts-file'."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/time ()
+(pcomplete-define "time" ()
   "Completion for the `time' command."
   (pcomplete-opt "p")
   (funcall pcomplete-command-completion-function)
@@ -97,7 +97,7 @@ being via `pcmpl-ssh-known-hosts-file'."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/which ()
+(pcomplete-define "which" ()
   "Completion for `which'."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "which --help")))
@@ -133,176 +133,191 @@ documentation), this function returns nil."
       (pcmpl-unix-read-passwd-file pcmpl-unix-passwd-file)))
 
 ;;;###autoload
-(defun pcomplete/cat ()
+(pcomplete-define "cat" ()
   "Completion for the `cat' command."
   (pcomplete-here-using-help "cat --help"))
 
 ;;;###autoload
-(defun pcomplete/tac ()
+(pcomplete-define "tac" ()
   "Completion for the `tac' command."
   (pcomplete-here-using-help "tac --help"))
 
 ;;;###autoload
-(defun pcomplete/nl ()
+(pcomplete-define "nl" ()
   "Completion for the `nl' command."
   (pcomplete-here-using-help "nl --help"))
 
 ;;;###autoload
-(defun pcomplete/od ()
+(pcomplete-define "od" ()
   "Completion for the `od' command."
   (pcomplete-here-using-help "od --help"))
 
 ;;;###autoload
-(defun pcomplete/base32 ()
+(pcomplete-define "base32" ()
   "Completion for the `base32' and `base64' commands."
   (pcomplete-here-using-help "base32 --help"))
-;;;###autoload
-(defalias 'pcomplete/base64 'pcomplete/base32)
 
 ;;;###autoload
-(defun pcomplete/basenc ()
+(pcomplete-alias "base64" "base32")
+
+;;;###autoload
+(pcomplete-define "basenc" ()
   "Completion for the `basenc' command."
   (pcomplete-here-using-help "basenc --help"))
 
 ;;;###autoload
-(defun pcomplete/fmt ()
+(pcomplete-define "fmt" ()
   "Completion for the `fmt' command."
   (pcomplete-here-using-help "fmt --help"))
 
 ;;;###autoload
-(defun pcomplete/pr ()
+(pcomplete-define "pr" ()
   "Completion for the `pr' command."
   (pcomplete-here-using-help "pr --help"))
 
 ;;;###autoload
-(defun pcomplete/fold ()
+(pcomplete-define "fold" ()
   "Completion for the `fold' command."
   (pcomplete-here-using-help "fold --help"))
 
 ;;;###autoload
-(defun pcomplete/head ()
+(pcomplete-define "head" ()
   "Completion for the `head' command."
   (pcomplete-here-using-help "head --help"))
 
 ;;;###autoload
-(defun pcomplete/tail ()
+(pcomplete-define "tail" ()
   "Completion for the `tail' command."
   (pcomplete-here-using-help "tail --help"))
 
 ;;;###autoload
-(defun pcomplete/split ()
+(pcomplete-define "split" ()
   "Completion for the `split' command."
   (pcomplete-here-using-help "split --help"))
 
 ;;;###autoload
-(defun pcomplete/csplit ()
+(pcomplete-define "csplit" ()
   "Completion for the `csplit' command."
   (pcomplete-here-using-help "csplit --help"))
 
 ;;;###autoload
-(defun pcomplete/wc ()
+(pcomplete-define "wc" ()
   "Completion for the `wc' command."
   (pcomplete-here-using-help "wc --help"))
 
 ;;;###autoload
-(defun pcomplete/sum ()
+(pcomplete-define "sum" ()
   "Completion for the `sum' command."
   (pcomplete-here-using-help "sum --help"))
 
 ;;;###autoload
-(defun pcomplete/cksum ()
+(pcomplete-define "cksum" ()
   "Completion for the `cksum' command."
   (pcomplete-here-using-help "cksum --help"))
 
 ;;;###autoload
-(defun pcomplete/b2sum ()
+(pcomplete-define "b2sum" ()
   "Completion for the `b2sum' command."
   (pcomplete-here-using-help "b2sum --help"))
 
 ;;;###autoload
-(defun pcomplete/md5sum ()
+(pcomplete-define "md5sum" ()
   "Completion for checksum commands."
   (pcomplete-here-using-help "md5sum --help"))
-;;;###autoload(defalias 'pcomplete/sha1sum 'pcomplete/md5sum)
-;;;###autoload(defalias 'pcomplete/sha224sum 'pcomplete/md5sum)
-;;;###autoload(defalias 'pcomplete/sha256sum 'pcomplete/md5sum)
-;;;###autoload(defalias 'pcomplete/sha384sum 'pcomplete/md5sum)
-;;;###autoload(defalias 'pcomplete/sha512sum 'pcomplete/md5sum)
 
 ;;;###autoload
-(defun pcomplete/sort ()
+(pcomplete-alias "sha1sum" "md5sum")
+
+;;;###autoload
+(pcomplete-alias "sha224sum" "md5sum")
+
+;;;###autoload
+(pcomplete-alias "sha256sum" "md5sum")
+
+;;;###autoload
+(pcomplete-alias "sha384sum" "md5sum")
+
+;;;###autoload
+(pcomplete-alias "sha512sum" "md5sum" )
+
+;;;###autoload
+(pcomplete-define "sort" ()
   "Completion for the `sort' command."
   (pcomplete-here-using-help "sort --help"))
 
 ;;;###autoload
-(defun pcomplete/shuf ()
+(pcomplete-define "shuf" ()
   "Completion for the `shuf' command."
   (pcomplete-here-using-help "shuf --help"))
 
 ;;;###autoload
-(defun pcomplete/uniq ()
+(pcomplete-define "uniq" ()
   "Completion for the `uniq' command."
   (pcomplete-here-using-help "uniq --help"))
 
 ;;;###autoload
-(defun pcomplete/comm ()
+(pcomplete-define "comm" ()
   "Completion for the `comm' command."
   (pcomplete-here-using-help "comm --help"))
 
 ;;;###autoload
-(defun pcomplete/ptx ()
+(pcomplete-define "ptx" ()
   "Completion for the `ptx' command."
   (pcomplete-here-using-help "ptx --help"))
 
 ;;;###autoload
-(defun pcomplete/tsort ()
+(pcomplete-define "tsort" ()
   "Completion for the `tsort' command."
   (pcomplete-here-using-help "tsort --help"))
 
 ;;;###autoload
-(defun pcomplete/cut ()
+(pcomplete-define "cut" ()
   "Completion for the `cut' command."
   (pcomplete-here-using-help "cut --help"))
 
 ;;;###autoload
-(defun pcomplete/paste ()
+(pcomplete-define "paste" ()
   "Completion for the `paste' command."
   (pcomplete-here-using-help "paste --help"))
 
 ;;;###autoload
-(defun pcomplete/join ()
+(pcomplete-define "join" ()
   "Completion for the `join' command."
   (pcomplete-here-using-help "join --help"))
 
 ;;;###autoload
-(defun pcomplete/tr ()
+(pcomplete-define "tr" ()
   "Completion for the `tr' command."
   (pcomplete-here-using-help "tr --help"))
 
 ;;;###autoload
-(defun pcomplete/expand ()
+(pcomplete-define "expand" ()
   "Completion for the `expand' command."
   (pcomplete-here-using-help "expand --help"))
 
 ;;;###autoload
-(defun pcomplete/unexpand ()
+(pcomplete-define "unexpand" ()
   "Completion for the `unexpand' command."
   (pcomplete-here-using-help "unexpand --help"))
 
 ;;;###autoload
-(defun pcomplete/ls ()
+(pcomplete-define "ls" ()
   "Completion for the `ls' command."
   (pcomplete-here-using-help "ls --help"))
-;;;###autoload(defalias 'pcomplete/dir 'pcomplete/ls)
-;;;###autoload(defalias 'pcomplete/vdir 'pcomplete/ls)
 
 ;;;###autoload
-(defun pcomplete/cp ()
+(pcomplete-alias "dir" "ls")
+
+;;;###autoload
+(pcomplete-alias "vdir" "ls")
+
+;;;###autoload
+(pcomplete-define "cp" ()
   "Completion for the `cp' command."
   (pcomplete-here-using-help "cp --help"))
 
 ;;;###autoload
-(defun pcomplete/dd ()
+(pcomplete-define "dd" ()
   "Completion for the `dd' command."
   (let ((operands (pcomplete-from-help "dd --help"
                                        :argument "[a-z]+="
@@ -315,47 +330,47 @@ documentation), this function returns nil."
               (t (pcomplete-here operands))))))
 
 ;;;###autoload
-(defun pcomplete/install ()
+(pcomplete-define "install" ()
   "Completion for the `install' command."
   (pcomplete-here-using-help "install --help"))
 
 ;;;###autoload
-(defun pcomplete/mv ()
+(pcomplete-define "mv" ()
   "Completion for the `mv' command."
   (pcomplete-here-using-help "mv --help"))
 
 ;;;###autoload
-(defun pcomplete/shred ()
+(pcomplete-define "shred" ()
   "Completion for the `shred' command."
   (pcomplete-here-using-help "shred --help"))
 
 ;;;###autoload
-(defun pcomplete/ln ()
+(pcomplete-define "ln" ()
   "Completion for the `ln' command."
   (pcomplete-here-using-help "ln --help"))
 
 ;;;###autoload
-(defun pcomplete/mkdir ()
+(pcomplete-define "mkdir" ()
   "Completion for the `mkdir' command."
   (pcomplete-here-using-help "mkdir --help"))
 
 ;;;###autoload
-(defun pcomplete/mkfifo ()
+(pcomplete-define "mkfifo" ()
   "Completion for the `mkfifo' command."
   (pcomplete-here-using-help "mkfifo --help"))
 
 ;;;###autoload
-(defun pcomplete/mknod ()
+(pcomplete-define "mknod" ()
   "Completion for the `mknod' command."
   (pcomplete-here-using-help "mknod --help"))
 
 ;;;###autoload
-(defun pcomplete/readlink ()
+(pcomplete-define "readlink" ()
   "Completion for the `readlink' command."
   (pcomplete-here-using-help "readlink --help"))
 
 ;;;###autoload
-(defun pcomplete/chown ()
+(pcomplete-define "chown" ()
   "Completion for the `chown' command."
   (while (pcomplete-match "\\`-" 0)
     (pcomplete-here (pcomplete-from-help "chown --help")))
@@ -368,7 +383,7 @@ documentation), this function returns nil."
   (while (pcomplete-here (pcomplete-entries))))
 
 ;;;###autoload
-(defun pcomplete/chgrp ()
+(pcomplete-define "chgrp" ()
   "Completion for the `chgrp' command."
   (while (pcomplete-match "\\`-" 0)
     (pcomplete-here (pcomplete-from-help "chgrp --help")))
@@ -376,131 +391,132 @@ documentation), this function returns nil."
   (while (pcomplete-here (pcomplete-entries))))
 
 ;;;###autoload
-(defun pcomplete/chmod ()
+(pcomplete-define "chmod" ()
   "Completion for the `chmod' command."
   (pcomplete-here-using-help "chmod --help"))
 
 ;;;###autoload
-(defun pcomplete/touch ()
+(pcomplete-define "touch" ()
   "Completion for the `touch' command."
   (pcomplete-here-using-help "touch --help"))
 
 ;;;###autoload
-(defun pcomplete/df ()
+(pcomplete-define "df" ()
   "Completion for the `df' command."
   (pcomplete-here-using-help "df --help"))
 
 ;;;###autoload
-(defun pcomplete/du ()
+(pcomplete-define "du" ()
   "Completion for the `du' command."
   (pcomplete-here-using-help "du --help"))
 
 ;;;###autoload
-(defun pcomplete/stat ()
+(pcomplete-define "stat" ()
   "Completion for the `stat' command."
   (pcomplete-here-using-help "stat --help"))
 
 ;;;###autoload
-(defun pcomplete/sync ()
+(pcomplete-define "sync" ()
   "Completion for the `sync' command."
   (pcomplete-here-using-help "sync --help"))
 
 ;;;###autoload
-(defun pcomplete/truncate ()
+(pcomplete-define "truncate" ()
   "Completion for the `truncate' command."
   (pcomplete-here-using-help "truncate --help"))
 
 ;;;###autoload
-(defun pcomplete/echo ()
+(pcomplete-define "echo" ()
   "Completion for the `echo' command."
   (pcomplete-here-using-help '("echo" "--help")))
 
 ;;;###autoload
-(defun pcomplete/test ()
+(pcomplete-define "test" ()
   "Completion for the `test' command."
   (pcomplete-here-using-help '("[" "--help")
                              :margin "^ +\\([A-Z]+1 \\)?"))
-;;;###autoload(defalias (intern "pcomplete/[") 'pcomplete/test)
+;;;###autoload
+(pcomplete-alias "[" "test")
 
 ;;;###autoload
-(defun pcomplete/tee ()
+(pcomplete-define "tee" ()
   "Completion for the `tee' command."
   (pcomplete-here-using-help "tee --help"))
 
 ;;;###autoload
-(defun pcomplete/basename ()
+(pcomplete-define "basename" ()
   "Completion for the `basename' command."
   (pcomplete-here-using-help "basename --help"))
 
 ;;;###autoload
-(defun pcomplete/dirname ()
+(pcomplete-define "dirname" ()
   "Completion for the `dirname' command."
   (pcomplete-here-using-help "dirname --help"))
 
 ;;;###autoload
-(defun pcomplete/pathchk ()
+(pcomplete-define "pathchk" ()
   "Completion for the `pathchk' command."
   (pcomplete-here-using-help "pathchk --help"))
 
 ;;;###autoload
-(defun pcomplete/mktemp ()
+(pcomplete-define "mktemp" ()
   "Completion for the `mktemp' command."
   (pcomplete-here-using-help "mktemp --help"))
 
 ;;;###autoload
-(defun pcomplete/realpath ()
+(pcomplete-define "realpath" ()
   "Completion for the `realpath' command."
   (pcomplete-here-using-help "realpath --help"))
 
 ;;;###autoload
-(defun pcomplete/id ()
+(pcomplete-define "id" ()
   "Completion for the `id' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "id --help")))
   (while (pcomplete-here (pcmpl-unix-user-names))))
 
 ;;;###autoload
-(defun pcomplete/groups ()
+(pcomplete-define "groups" ()
   "Completion for the `groups' command."
   (while (pcomplete-here (pcmpl-unix-user-names))))
 
 ;;;###autoload
-(defun pcomplete/who ()
+(pcomplete-define "who" ()
   "Completion for the `who' command."
   (pcomplete-here-using-help "who --help"))
 
 ;;;###autoload
-(defun pcomplete/date ()
+(pcomplete-define "date" ()
   "Completion for the `date' command."
   (pcomplete-here-using-help "date --help"))
 
 ;;;###autoload
-(defun pcomplete/nproc ()
+(pcomplete-define "nproc" ()
   "Completion for the `nproc' command."
   (pcomplete-here-using-help "nproc --help"))
 
 ;;;###autoload
-(defun pcomplete/uname ()
+(pcomplete-define "uname" ()
   "Completion for the `uname' command."
   (pcomplete-here-using-help "uname --help"))
 
 ;;;###autoload
-(defun pcomplete/hostname ()
+(pcomplete-define "hostname" ()
   "Completion for the `hostname' command."
   (pcomplete-here-using-help "hostname --help"))
 
 ;;;###autoload
-(defun pcomplete/uptime ()
+(pcomplete-define "uptime" ()
   "Completion for the `uptime' command."
   (pcomplete-here-using-help "uptime --help"))
 
 ;;;###autoload
-(defun pcomplete/chcon ()
+(pcomplete-define "chcon" ()
   "Completion for the `chcon' command."
   (pcomplete-here-using-help "chcon --help"))
 
 ;;;###autoload
-(defun pcomplete/runcon ()
+(pcomplete-define "runcon" ()
   "Completion for the `runcon' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "runcon --help"))
@@ -510,7 +526,7 @@ documentation), this function returns nil."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/chroot ()
+(pcomplete-define "chroot" ()
   "Completion for the `chroot' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "chroot --help")))
@@ -520,7 +536,7 @@ documentation), this function returns nil."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/env ()
+(pcomplete-define "env" ()
   "Completion for the `env' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "env --help"))
@@ -531,7 +547,7 @@ documentation), this function returns nil."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/nice ()
+(pcomplete-define "nice" ()
   "Completion for the `nice' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "nice --help"))
@@ -541,7 +557,7 @@ documentation), this function returns nil."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/nohup ()
+(pcomplete-define "nohup" ()
   "Completion for the `nohup' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "nohup --help")))
@@ -550,7 +566,7 @@ documentation), this function returns nil."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/stdbuf ()
+(pcomplete-define "stdbuf" ()
   "Completion for the `stdbuf' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "stdbuf --help"))
@@ -560,7 +576,7 @@ documentation), this function returns nil."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/timeout ()
+(pcomplete-define "timeout" ()
   "Completion for the `timeout' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "timeout --help"))
@@ -571,12 +587,12 @@ documentation), this function returns nil."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/numfmt ()
+(pcomplete-define "numfmt" ()
   "Completion for the `numfmt' command."
   (pcomplete-here-using-help "numfmt --help"))
 
 ;;;###autoload
-(defun pcomplete/seq ()
+(pcomplete-define "seq" ()
   "Completion for the `seq' command."
   (pcomplete-here-using-help "seq --help"))
 
@@ -626,17 +642,19 @@ Uses both `pcmpl-ssh-config-file' and `pcmpl-ssh-known-hosts-file'."
     hosts))
 
 ;;;###autoload
-(defun pcomplete/ssh ()
+(pcomplete-define "ssh" ()
   "Completion rules for the `ssh' command."
   (pcomplete-opt "1246AaCfgKkMNnqsTtVvXxYbcDeFiLlmOopRSw")
   (pcomplete-here (pcmpl-ssh-hosts)))
 
 ;;;###autoload
-(defalias 'pcomplete/rsh    #'pcomplete/ssh)
-(defalias 'pcomplete/rlogin #'pcomplete/ssh)
+(pcomplete-alias "rsh" "ssh")
 
 ;;;###autoload
-(defun pcomplete/scp ()
+(pcomplete-alias "rlogin" "ssh")
+
+;;;###autoload
+(pcomplete-define "scp" ()
   "Completion rules for the `scp' command.
 Includes files as well as host names followed by a colon."
   (pcomplete-opt "1246BCpqrvcFiloPS")
@@ -664,19 +682,19 @@ Includes files as well as host names followed by a colon."
   "Complete a command that wants a hostname for an argument."
   (pcomplete-here (pcomplete-read-host-names)))
 
-(defalias 'pcomplete/ftp    'pcmpl-unix-complete-hostname)
-(defalias 'pcomplete/ncftp  'pcmpl-unix-complete-hostname)
-(defalias 'pcomplete/ping   'pcmpl-unix-complete-hostname)
+(pcomplete-define "ftp"   () (pcmpl-unix-complete-hostname))
+(pcomplete-define "ncftp" () (pcmpl-unix-complete-hostname))
+(pcomplete-define "ping"  () (pcmpl-unix-complete-hostname))
 
 ;;;###autoload
-(defun pcomplete/telnet ()
+(pcomplete-define "telnet" ()
   (pcomplete-opt "xl(pcmpl-unix-user-names)")
   (pcmpl-unix-complete-hostname))
 
 ;;; Miscellaneous
 
 ;;;###autoload
-(defun pcomplete/sudo ()
+(pcomplete-define "sudo" ()
   "Completion for the `sudo' command."
   (while (string-prefix-p "-" (pcomplete-arg 0))
     (pcomplete-here (pcomplete-from-help "sudo --help"))
@@ -686,7 +704,7 @@ Includes files as well as host names followed by a colon."
 	       pcomplete-default-completion-function)))
 
 ;;;###autoload
-(defun pcomplete/doas ()
+(pcomplete-define "doas" ()
   "Completion for the `doas' command."
   (pcomplete-opt "C(pcomplete-entries)Lnsu(pcmpl-unix-user-names)")
   (funcall pcomplete-command-completion-function)
diff --git a/lisp/pcmpl-x.el b/lisp/pcmpl-x.el
index 7d8b9e92da2..ad3e220304e 100644
--- a/lisp/pcmpl-x.el
+++ b/lisp/pcmpl-x.el
@@ -31,19 +31,26 @@
 ;;; TeX
 
 ;;;###autoload
-(defun pcomplete/tex ()
+(pcomplete-define "tex" ()
   "Completion for the `tex' command."
   (pcomplete-here-using-help "tex --help"
                              :margin "^\\(?:\\[-no\\]\\)?\\(\\)-"))
-;;;###autoload(defalias 'pcomplete/pdftex 'pcomplete/tex)
-;;;###autoload(defalias 'pcomplete/latex 'pcomplete/tex)
-;;;###autoload(defalias 'pcomplete/pdflatex 'pcomplete/tex)
+;;;###autoload
+(pcomplete-alias "pdftex" "tex")
 
 ;;;###autoload
-(defun pcomplete/luatex ()
+(pcomplete-alias "latex" "tex")
+
+;;;###autoload
+(pcomplete-alias "pdflatex" "tex")
+
+;;;###autoload
+(pcomplete-define "luatex" ()
   "Completion for the `luatex' command."
   (pcomplete-here-using-help "luatex --help"))
-;;;###autoload(defalias 'pcomplete/lualatex 'pcomplete/luatex)
+
+;;;###autoload
+(pcomplete-alias "lualatex" "luatex")
 
 ;;;; tlmgr - https://www.tug.org/texlive/tlmgr.html
 
@@ -137,7 +144,7 @@
     (gethash action pcmpl-x-tlmgr-options-cache)))
 
 ;;;###autoload
-(defun pcomplete/tlmgr ()
+(pcomplete-define "tlmgr" ()
   "Completion for the `tlmgr' command."
   (while (pcomplete-match "^--" 0)
     (pcomplete-here* pcmpl-x-tlmgr-common-options)
@@ -161,7 +168,7 @@
 ;;; Grep-like tools
 
 ;;;###autoload
-(defun pcomplete/rg ()
+(pcomplete-define "rg" ()
   "Completion for the `rg' command."
   (pcomplete-here-using-help "rg --help"))
 
@@ -245,7 +252,7 @@
   (pcmpl-x-ack-long-options "--help-types"))
 
 ;;;###autoload
-(defun pcomplete/ack ()
+(pcomplete-define "ack" ()
   "Completion for the `ack' command.
 Start an argument with `-' to complete short options and `--' for
 long options."
@@ -271,7 +278,7 @@ long options."
       (pcomplete-here* (pcomplete-dirs-or-entries)))))
 
 ;;;###autoload
-(defalias 'pcomplete/ack-grep 'pcomplete/ack)
+(pcomplete-define "ack-grep" () (pcomplete/ack))
 
 
 ;;;; the_silver_search - https://github.com/ggreer/the_silver_searcher
@@ -302,7 +309,7 @@ long options."
                         (cons 'long  (nreverse long)))))))))
 
 ;;;###autoload
-(defun pcomplete/ag ()
+(pcomplete-define "ag" ()
   "Completion for the `ag' command."
   (while t
     (if (pcomplete-match "^-" 0)
@@ -313,7 +320,7 @@ long options."
 ;;; Borland
 
 ;;;###autoload
-(defun pcomplete/bcc32 ()
+(pcomplete-define "bcc32" ()
   "Completion function for Borland's C++ compiler."
   (let ((cur (pcomplete-arg 0)))
     (cond
@@ -343,12 +350,12 @@ long options."
           (pcomplete-dirs-or-entries "\\.[iCc]\\([Pp][Pp]\\)?\\'"))))
 
 ;;;###autoload
-(defalias 'pcomplete/bcc 'pcomplete/bcc32)
+(pcomplete-define "bcc" () (pcomplete/bcc32))
 
 ;;; Network tools
 
 ;;;###autoload
-(defun pcomplete/rclone ()
+(pcomplete-define "rclone" ()
   "Completion for the `rclone' command."
   (let ((subcmds (pcomplete-from-help "rclone help"
                                       :margin "^  "
diff --git a/lisp/pcomplete.el b/lisp/pcomplete.el
index 65ccfd9700c..3a820a20876 100644
--- a/lisp/pcomplete.el
+++ b/lisp/pcomplete.el
@@ -41,17 +41,16 @@
 ;; filenames for the first two arguments, and directories for all
 ;; remaining arguments:
 ;;
-;;   (defun pcomplete/my-command ()
+;;   (pcomplete-define "my-command" ()
 ;;     (pcomplete-here (pcomplete-entries))
 ;;     (pcomplete-here (pcomplete-entries))
 ;;     (while (pcomplete-here (pcomplete-dirs))))
 ;;
 ;; Here are the requirements for completion functions:
 ;;
-;; @ They must be called "pcomplete/MAJOR-MODE/NAME", or
-;;   "pcomplete/NAME".  This is how they are looked up, using the NAME
-;;   specified in the command argument (the argument in first
-;;   position).
+;; @ They must be defined with `pcomplete-define', using a NAME such
+;;   as "MAJOR-MODE/COMMAND" or just "COMMAND".  This is how they are
+;;   looked up, using the command name in the first argument position.
 ;;
 ;; @ They must be callable with no arguments.
 ;;
@@ -123,6 +122,26 @@
   (require 'cl-lib)
   (require 'rx))
 
+(defmacro pcomplete-define (name arglist &rest body)
+  "Define a pcomplete completion function for NAME.
+NAME is a string like \"cd\" or \"erc-mode/MSG\".
+Registers a lambda in `pcomplete--obarray' for dispatch.
+ARGLIST and BODY are as in `defun'."
+  (declare (indent defun) (autoload-macro expand))
+  `(progn
+     (pcomplete--autoload ,name ,load-true-file-name)
+     :autoload-end
+     (put (intern ,name pcomplete--obarray) 'pcomplete-function (lambda ,arglist ,@body))))
+
+(defmacro pcomplete-alias (alias name)
+  "Say that ALIAS should have the same completion function as NAME."
+  (declare (indent defun) (autoload-macro expand))
+  `(progn
+     (pcomplete--autoload ,name ,load-true-file-name)
+     :autoload-end
+     (put (intern ,alias pcomplete--obarray) 'pcomplete-function
+          (get (intern ,name pcomplete--obarray) 'pcomplete-function))))
+
 (defgroup pcomplete nil
   "Programmable completion."
   :version "21.1"
@@ -994,11 +1013,22 @@ component, `default-directory' is used as the basis for completion."
 
 (defun pcomplete-find-completion-function (command)
   "Find the completion function to call for the given COMMAND."
-  (let ((sym (intern-soft
-	      (concat "pcomplete/" (symbol-name major-mode) "/" command))))
-    (unless sym
-      (setq sym (intern-soft (concat "pcomplete/" command))))
-    (and sym (fboundp sym) sym)))
+  (let* ((sym (or (intern-soft (concat (symbol-name major-mode) "/" command)
+                               pcomplete--obarray)
+                  (intern-soft command pcomplete--obarray)))
+         (fun (and (get sym 'pcomplete-function))))
+    ;; Lazy-load the file if registered via `pcomplete-attach'.
+    (when-let* ((file (and sym (null fun) (get sym 'pcomplete-autoload))))
+      (require (intern file))
+      (setq fun (get sym 'pcomplete-function)))
+    (cond (fun)
+          ;; Backward compatibility: fall back to global obarray for packages
+          ;; that still use the old `defun pcomplete/...' naming convention.
+          ((and (setq sym (or (intern-soft
+                               (concat "pcomplete/" (symbol-name major-mode) "/" command))
+                              (intern-soft (concat "pcomplete/" command))))
+                (fboundp sym))
+           sym))))
 
 (defun pcomplete-completions ()
   "Return a list of completions for the current argument position."
diff --git a/lisp/subr.el b/lisp/subr.el
index 0ad86fd30a1..b7d2a2865c2 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -8032,4 +8032,13 @@ and return the value found in PLACE instead."
       ((pred numberp) v)
       (`(,above . ,below) (+ above below)))))
 
+(defvar pcomplete--obarray (obarray-make)
+  "Special obarry for Pcomplete commands")
+
+(defun pcomplete--autoload (name file)
+  "Make a note to lazy-load pcomplete command NAME from FILE."
+  (unless (get (intern name pcomplete--obarray) 'pcomplete-autoload)
+    (put (intern name pcomplete--obarray) 'pcomplete-autoload file)))
+
+
 ;;; subr.el ends here