diff --git a/spacy/kb/kb.pxd b/spacy/kb/kb.pxd
index 1adeef8ae..ff2fc15ce 100644
--- a/spacy/kb/kb.pxd
+++ b/spacy/kb/kb.pxd
@@ -7,4 +7,4 @@ from ..vocab cimport Vocab
 cdef class KnowledgeBase:
     cdef Pool mem
     cdef readonly Vocab vocab
-    cdef readonly int64_t entity_vector_length
+    cdef int64_t entity_vector_length