diff --git a/index.html b/index.html
index 8686c35..7dca5e7 100644
--- a/index.html
+++ b/index.html
@@ -1058,7 +1058,7 @@ <h3 id="MIDIOutput">
                 a [=valid MIDI message=], throw a <code>TypeError</code> exception.
               </p>
               <p>
-                If <var>data</var> is a [=System Exclusive=] message, and the
+                If <var>data</var> contains a [=System Exclusive=] message and the
                 {{MIDIAccess}} did not enable [=System Exclusive=] access, throw
                 an <code>NotAllowedError</code> exception.
               </p>