diff --git a/src/cli.rs b/src/cli.rs
index 016d64e..3039405 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -29,7 +29,7 @@ Suffixes attach to a group, in any order, case-insensitive. Rerolls and
 minimums settle before a keep/drop suffix picks which dice count.
   khN, klN   keep the highest/lowest N; bare kh/kl keeps 1
   dhN, dlN   drop the highest/lowest N
-  roN        reroll a die once, keeping the new value
+  roN        reroll once when the roll equals N, keeping the new value
   ro<N       reroll once when the roll is less than N
   ro>N       reroll once when the roll is greater than N
   rN         reroll a die until the roll no longer equals N