n the concentration of attention or energy on something
n maximum clarity or distinctness of an image rendered by an optical system
n maximum clarity or distinctness of an idea
n a central point or locus of an infection in an organism
n special emphasis attached to something
n a point of convergence of light (or other radiation) or a point from which it diverges
n a fixed reference point on the concave side of a conic section
pl. 焦点, 焦距, 对焦点, 聚焦, 活动中心, 集中点, 兴趣中心, 病灶, 震源, 疫源地