Adds Clarification for kerning vs spacing/tracking. Fixes mdn#35579

files/en-us/web/css/font-kerning/index.md

@@ -11,7 +11,7 @@ The **`font-kerning`** [CSS](/en-US/docs/Web/CSS) property sets the use of the k
 
 {{EmbedInteractiveExample("pages/css/font-kerning.html")}}
 
-_Kerning_ defines how letters are spaced. In _well-kerned_ fonts, this feature makes character spacing more uniform and pleasant to read than it would otherwise be.
+_Kerning_ affects how letters are spaced. In _well-kerned_ fonts, this feature makes character spacing more uniform and pleasant to read by adjusting spacing for certain letter combinations, which would otherwise have a lot more white space.
 
 In the image below, for instance, the examples on the left do not use kerning, while the ones on the right do: