- (optics) A focus; a point at which rays of light or other radiation converge.
- The centre of any activity.
- 2006, Edwin Black, chapter 2, in Internal Combustion:
- Throughout the 1500s, the populace roiled over a constellation of grievances of which the forest emerged as a key focal point. The popular late Middle Ages fictional character Robin Hood, dressed in green to symbolize the forest, dodged fines for forest offenses and stole from the rich to give to the poor. But his appeal was painfully real and embodied the struggle over wood.
- (art, aesthetics) A feature that attracts particular attention.
- (game theory) A solution that people will tend to use in the absence of communication, because it seems natural, special, or relevant.
(optics) a focus; a point at which rays of light or other radiation converge