diff --git a/lisp/progmodes/ebnf-dtd.el b/lisp/progmodes/ebnf-dtd.el
index 621cf424463..2f1d6412d38 100644
--- a/lisp/progmodes/ebnf-dtd.el
+++ b/lisp/progmodes/ebnf-dtd.el
@@ -1152,7 +1152,7 @@
 
 
 (defun ebnf-dtd-lex ()
-  "Lexical analyser for DTD.
+  "Lexical analyzer for DTD.
 
 Return a lexical token.