Clarified scrollable container

index.bs

@@ -673,7 +673,7 @@ run these steps:
 		of the {{document}}, and update |container| to be
 		the <a>browsing context container</a> of |container|.
 	2. Map |intersectionRect| to the coordinate space of |container|.
-	3. If |container| is scrollable, apply the {{IntersectionObserver}}’s
+	3. If |container| is a <a href="https://www.w3.org/TR/css-overflow/#scroll-container">scroll-container</a>, apply the {{IntersectionObserver}}’s
 		{{[[scrollMargin]]}} to the |container|'s clip rect.
 	4. If |container| has a <a>content clip</a> or a css <a>clip-path</a> property,
 		update |intersectionRect| by applying |container|'s clip.