diff --git a/core/bootstrap/syntax.factor b/core/bootstrap/syntax.factor
index 9f922e0d99..c03f029fb8 100644
--- a/core/bootstrap/syntax.factor
+++ b/core/bootstrap/syntax.factor
@@ -106,6 +106,7 @@ IN: bootstrap.syntax
         "BROADCAST:"
         "SLOT-PROTOCOL:"
         "HINTS:"
+        "':"
         "'["
         "@"
         "_"