diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index e2ce176..4024d20 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -5638,22 +5638,24 @@
 'messagesopt' 'mopt'	string	(default "hit-enter,history:500")
 			global
 
-	Option settings when outputting messages.  It can consist of the
+	Option settings for outputting messages.  It can consist of the
 	following items.  Items must be separated by a comma.
 
-	hit-enter	Use |hit-enter| prompt when the message is longer than
+	hit-enter	Use a |hit-enter| prompt when the message is longer than
 			'cmdheight' size.
 
-	wait:{n}	Ignored when "hit-enter" is present.  Instead of using
-			|hit-enter| prompt, will simply wait for {n}
-			milliseconds so the user has a chance to read the
-			message, use 0 to disable sleep (but then the user may
-			miss an important message).
-			The maximum value is 10000.
+	wait:{n}	Instead of using a |hit-enter| prompt, simply wait for
+			{n} milliseconds so that the user has a chance to read
+			the message.  The maximum value of {n} is 10000.  Use
+			0 to disable the wait (but then the user may miss an
+			important message).
+			This item is ignored when "hit-enter" is present, but
+			required when "hit-enter" is not present.
 
 	history:{n}	Determines how many entries are remembered in the
 			|:messages| history.  The maximum value is 10000.
 			Setting it to zero clears the message history.
+			This item must always be present.
 
 						*'mkspellmem'* *'msm'*
 'mkspellmem' 'msm'	string	(default "460000,2000,500")