diff --git a/doc/manual.adoc b/doc/manual.adoc
index ec818b7..1e84a92 100644
--- a/doc/manual.adoc
+++ b/doc/manual.adoc
@@ -65,6 +65,12 @@ specified in <<_schema_file>> and <<_configuration_file>>.  They must appear
 only at the very beginning of a schema or configuration file.  In particular, it
 is not allowed for them to be preceded by a byte order mark.
 
+==== Table Definition Directives (`def`)
+
+A table definition directive consists of a record containing the values `def`
+and the table name.  A table must be defined before any field definitions can
+occur for that table.
+
 === Configuration File
 
 Configuration files are identical to schema files except that instead of the