diff --git a/jsonata.d.ts b/jsonata.d.ts
index 257aac0..a8c68f7 100644
--- a/jsonata.d.ts
+++ b/jsonata.d.ts
@@ -20,7 +20,7 @@ declare namespace jsonata {
     steps?: ExprNode[];
     expressions?: ExprNode[];
     stages?: ExprNode[];
-    lhs?: ExprNode[];
+    lhs?: ExprNode;
     rhs?: ExprNode;
   }