Restore #3536 (probably lost in merge conflicts)

guidelines/terms/21/single-pointer.html

@@ -1,7 +1,6 @@
 <dt><dfn id="dfn-single-pointer">single pointer</dfn></dt>
 <dd>
-
-  <p><a>pointer input</a> that operates with one point of contact with the screen, including single taps and clicks, double-taps and clicks, long presses, and path-based gestures</p>
-
+  <p>a <a>pointer input</a> that only targets a single point on the page/screen at a time – such as a mouse, single finger on a touch screen, or stylus.</p>
+  <p class="note">In contrast to single pointer inputs, multipoint interactions involve the use of two or more pointers at the same time – such as two finger interactions on a touchscreen, or the simultaneous use of a mouse and stylus.</p>
 </dd>