diff --git a/doc/PROTOCOL b/doc/PROTOCOL
index 65be154..1a123fe 100644
--- a/doc/PROTOCOL
+++ b/doc/PROTOCOL
@@ -326,7 +326,7 @@ RDIRENT.HEADER types:
 		file position:	offset in file
 		data:           ASCIIZ filename
 		xtra data:	(not required)
-		                word - size of reply's optional data block
+		                word - preferred size of reply's data block
 
 		reply
 		file position:  same as in request