[css-sizing-4] Define term 'preferred aspect ratio'

Author: fantasai

css-sizing-4/Overview.bs

@@ -78,29 +78,31 @@ Intrinsic Aspect Ratios: the 'aspect-ratio' property</h3>
 	Computed value: specified keyword or a pair of numbers
 	</pre>
 
-	This property sets an intrinsic aspect ratio for the box,
+	This property sets a <dfn export>preferred aspect ratio</dfn> for the box,
 	which will be used in the calculation of ''height/auto'' sizes
 	and some other layout functions.
-	The box will essentially size the same as a <a>replaced element</a>
-	with an <a>intrinsic aspect ratio</a>,
-	see e.g. <a href="https://www.w3.org/TR/CSS2/visudet.html">CSS2&sect;10</a>.
+	The box’s <a>automatic sizes</a>
+	are then calculated the same as for
+	a <a>replaced element</a> with an <a>intrinsic aspect ratio</a>,
+	see <a href="https://www.w3.org/TR/CSS2/visudet.html">CSS2&sect;10</a>.
 
 	<dl dfn-for="aspect-ratio" dfn-type="value">
 		<dt><dfn>auto</dfn>
 		<dd>
 			<a>Replaced elements</a> with an <a>intrinsic aspect ratio</a>
 			use that aspect ratio;
-			otherwise the box has no aspect ratio.
+			otherwise the box has no <a>preferred aspect ratio</a>.
 
 		<dt><dfn><<ratio>></dfn>
 		<dd>
-			The box’s aspect ratio is the specified ratio.
+			The box’s <a>preferred aspect ratio</a> is the specified ratio
+			of ''<var>width</var> / <var>height</var>''.
 	</dl>
 
 	Note: If a box has both a specified 'width' and a specified 'height',
-	then the aspect ratio has no effect:
+	then the <a>preferred aspect ratio</a> has no effect:
 	at least one of these sizes must be ''width/auto''
-	for the aspect ratio to have an impact on sizing.
+	for the <dfn>preferred aspect ratio</a> to have an impact on sizing.
 
 	<div class="example">
 		This example sets each item in the grid to render as a square,