Points where light rays or lines converge in optics or geometry.

• The fixed points defining a conic section.

光学或几何中光线或直线汇聚的点。

• 圆锥曲线的固定点。

Central points of attention, activity, or interest.

注意力、活动或兴趣集中的中心点。

Subsurface points where earthquakes originate, beneath the epicenters.

地震在震中下方开始的地下起源点。

Localized sites of disease or infection within tissue.

组织内局部的疾病或感染灶。