It's the input that's null

Author: jakearchibald

css-easing-1/Overview.bs

@@ -143,11 +143,13 @@ that has:
 <dl dfn-for="linear easing point">
 
 : <dfn>input</dfn>
-:: A number
-: <dfn>output</dfn>
 :: A number or null
 
-      Note: The [=linear easing point/output=] is only null during the [=create a linear easing function=] algorithm.
+      Note: The [=linear easing point/input=] is only null during the [=create a linear easing function=] algorithm.
+
+: <dfn>output</dfn>
+:: A number
+
 
 </dl>