diff --git a/doc/misc/ada-mode.texi b/doc/misc/ada-mode.texi
index 374158c2c78..0eb20d01324 100644
--- a/doc/misc/ada-mode.texi
+++ b/doc/misc/ada-mode.texi
@@ -1357,7 +1357,7 @@ specifies the casing of one word or word fragment. Comments may be
 included, separated from the word by a space.
 
 If the word starts with an asterisk (@key{*}), it defines the casing
-af a word fragment (or ``substring''); part of a word between two
+as a word fragment (or ``substring''); part of a word between two
 underscores or word boundary.
 
 For example: