diff --git a/node.c b/node.c
index 521ddf690a..eb88efc61a 100644
--- a/node.c
+++ b/node.c
@@ -216,7 +216,7 @@ dump_node(VALUE buf, VALUE indent, int comment, const NODE * node)
 
       case NODE_IN:
         ANN("in clause");
-        ANN("format: in [nd_head]; [nd_body]; (when or else) [nd_next]");
+        ANN("format: in [nd_head]; [nd_body]; (in or else) [nd_next]");
         ANN("example: case x; in 1; foo; in 2; bar; else baz; end");
         F_NODE(nd_head, "in value");
         F_NODE(nd_body, "in body");