diff --git a/css-sizing/Overview.bs b/css-sizing/Overview.bs
index 367d0303e7a..b8d69c415fc 100644
--- a/css-sizing/Overview.bs
+++ b/css-sizing/Overview.bs
@@ -82,9 +82,9 @@ Terminology
definite size
A size that can be determined without measuring content;
- that is, a <length>,
+ that is, a <>,
a size of the initial containing block,
- or a <percentage> that is resolved against a definite size.
+ or a <> or other formula that is resolved solely against definite sizes.
Additionally, the size of the containing block of an absolutely positioned element is always definite
with respect to that element.