diff --git a/proto/protocol.xml b/proto/protocol.xml
index f0d67e4..9f29d69 100644
--- a/proto/protocol.xml
+++ b/proto/protocol.xml
@@ -740,7 +740,7 @@
         zero offset region spanning the left screen, the second with a nonzero
         offset spanning the right screen.
 
-        The physical scale denotes a constant factor that needs to be applied to
+        The physical scale denotes a constant multiplication factor that needs to be applied to
         any relative movement on this region for that movement to match the same
         *physical* movement on another region.