focal point

(noun) a point of convergence of light (or other radiation) or a point from which it diverges. Synonyms: focus, focal point.

(noun) a central point or locus of an infection in an organism. Synonyms: focus, focal point, nidus. Example: "The focus of infection."

(noun) the concentration of attention or energy on something. Synonyms: focus, focusing, focussing, focal point, direction, centering. Examples: "The focus of activity shifted to molecular biology." "He had no direction in his life."