diff --git a/docs/mm.1 b/docs/mm.1
index 42a3e74..01790fd 100644
--- a/docs/mm.1
+++ b/docs/mm.1
@@ -26,7 +26,7 @@ Catenate input files and write them to the start of each output file or stream.
 
 .B -a
 .RS
-Opens outputs for appending rather than updating.
+Opens subsequent outputs for appending rather than updating.
 .RE
 
 .B -e