diff --git a/basis/stack-checker/known-words/known-words.factor b/basis/stack-checker/known-words/known-words.factor
index d6a92cbf08..7e9ce01206 100644
--- a/basis/stack-checker/known-words/known-words.factor
+++ b/basis/stack-checker/known-words/known-words.factor
@@ -344,6 +344,7 @@ M: object infer-call* \ call bad-macro-input ;
 \ bignum> { bignum bignum } { object } define-primitive \ bignum> make-foldable
 \ bignum>= { bignum bignum } { object } define-primitive \ bignum>= make-foldable
 \ bignum>fixnum { bignum } { fixnum } define-primitive \ bignum>fixnum make-foldable
+\ bignum>fixnum-strict { bignum } { fixnum } define-primitive \ bignum>fixnum-strict make-foldable
 \ bits>double { integer } { float } define-primitive \ bits>double make-foldable
 \ bits>float { integer } { float } define-primitive \ bits>float make-foldable
 \ both-fixnums? { object object } { object } define-primitive