diff --git a/basis/stack-checker/known-words/known-words.factor b/basis/stack-checker/known-words/known-words.factor
index 471879673f..17a66653cb 100644
--- a/basis/stack-checker/known-words/known-words.factor
+++ b/basis/stack-checker/known-words/known-words.factor
@@ -302,7 +302,7 @@ M: object infer-call* \ call bad-macro-input ;
 \ (word) { object object object } { word } define-primitive \ (word) make-flushable
 \ <array> { integer object } { array } define-primitive \ <array> make-flushable
 \ <byte-array> { integer } { byte-array } define-primitive \ <byte-array> make-flushable
-\ <callback> { integer word } { alien } define-primitive
+\ <callback> { word integer } { alien } define-primitive
 \ <displaced-alien> { integer c-ptr } { c-ptr } define-primitive \ <displaced-alien> make-flushable
 \ <string> { integer integer } { string } define-primitive \ <string> make-flushable
 \ <tuple> { array } { tuple } define-primitive \ <tuple> make-flushable
diff --git a/core/bootstrap/primitives.factor b/core/bootstrap/primitives.factor
index fc5649470c..d67189ac02 100755
--- a/core/bootstrap/primitives.factor
+++ b/core/bootstrap/primitives.factor
@@ -398,7 +398,7 @@ tuple
     ] dip define-declared ;
 
 {
-    { "<callback>" "alien" "primitive_callback" ( return-rewind word -- alien ) }
+    { "<callback>" "alien" "primitive_callback" ( word return-rewind -- alien ) }
     { "<displaced-alien>" "alien" "primitive_displaced_alien" ( displacement c-ptr -- alien ) }
     { "alien-address" "alien" "primitive_alien_address" ( c-ptr -- addr ) }
     { "alien-cell" "alien.accessors" "primitive_alien_cell" ( c-ptr n -- value ) }