by an option, not a command. @xref{Apropos}.
@item M-x apropos-documentation @var{topic} @key{RET}
-This searches the @emph{documentation strings} of all variables and
-functions (not their names) for a match for @var{topic}, a regular
-expression. @xref{Apropos}.
+This searches the @emph{documentation strings} (the built-in short
+descriptions) of all variables and functions (not their names) for a
+match for @var{topic}, a regular expression. @xref{Apropos}.
@item C-h i emacs @key{RET} i @var{topic} @key{RET}
This looks up @var{topic} in the indices of the Emacs on-line manual.