[jiāo diǎn]
[數] [物] （二次曲線焦點； 主焦點） focal point; focus
virtual focus
虛焦點
principal focus
主焦點
defocus
焦點分散
（問題的關鍵所在或爭論的集中點） central issue; centre; point at issue
the focus of the struggle
斗爭的焦點
focal points of contradictions
矛盾的焦點
the heart of the matter
問題的焦點
the points at issue
爭論的焦點
[氣] origin
[冶] （焦斑） focal spot