diff --git a/modules/src/string/string.3 b/modules/src/string/string.3
index e4ea42d1e..27de210e6 100644
--- a/modules/src/string/string.3
+++ b/modules/src/string/string.3
@@ -141,6 +141,11 @@ or zero if
 does not occur in
 .IR s .
 .PP
+.I Strzero
+turns
+.I s
+into a null string.
+.PP
 .I Bts2str
 turns a row of
 .I n