diff --git a/docs/querying/operators.md b/docs/querying/operators.md
index 9054b97a56..6367f6e73c 100644
--- a/docs/querying/operators.md
+++ b/docs/querying/operators.md
@@ -74,7 +74,7 @@ corresponding element from the output vector, flagged by an info-level
 annotation.
 
 **In any arithmetic binary operation involving vectors**, the metric name is
-dropped.
+dropped unless it is explicitly mentioned in `on`.
 
 ### Trigonometric binary operators