focal point
noun uk/ˌfəʊ.kəl ˈpɔɪnt/ us/ˌfoʊ.kəl ˈpɔɪnt/
(INTEREST)
[ C usually singular ]（目光或兴趣的）中心，焦点
the thing that everyone looks at or is interested in
The fireplace is usually the focal point of the living room. 在客厅里，壁炉通常是视线的焦点。
(SCIENCE)
[ C ] physics specialized焦点，聚光点
the point where waves of light or sound that are moving towards each other meet