diff --git a/include/tvm/relay/type.h b/include/tvm/relay/type.h
index 6612cfaea88a9..e2a0c2a2a7ed4 100644
--- a/include/tvm/relay/type.h
+++ b/include/tvm/relay/type.h
@@ -82,7 +82,9 @@ class TensorTypeNode : public BaseTensorTypeNode {
     v->Visit("span", &span);
   }
 
-  /*! \brief Return product of elements in the shape */
+  /*! \brief Return product of elements in the shape.
+   *  \return (d1 * d_2 ... * d_n) if shape is (d_1, d_2, ..., d_n) and 1 if shape size is zero.
+   */
   TVM_DLL IndexExpr Size() const;
 
   TVM_DLL static TensorType make(Array<IndexExpr> shape, DataType dtype);