diff --git a/ontobio/model/nlp.py b/ontobio/model/nlp.py
index 675d0a28..459173e4 100644
--- a/ontobio/model/nlp.py
+++ b/ontobio/model/nlp.py
@@ -16,7 +16,7 @@ class Token:
     A token or entity extracted from a marked-up span
     """
     id: str
-    category: List[str] = field(default_factory=list)
+    categories: List[str] = field(default_factory=list)
     terms: List[str] = field(default_factory=list)