- (n.) A point so related to a conic section and certain straight line called the directrix that the ratio of the distace between any point of the curve and the focus to the distance of the same point from the directrix is constant.
- (v.t.) To bring to a focus; to focalize; as, to focus a camera.
- (n.) A point in which the rays of light meet, after being reflected or refrcted, and at which the image is formed; as, the focus of a lens or mirror.
- (n.) A central point; a point of concentration.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). focus. Retrieved September 23, 2026, from http://smartdefine.org/focus/definitions/2009051 |
| Chicago | Webster's. 2011. "focus" http://smartdefine.org/focus/definitions/2009051 (accessed September 23, 2026). |
| Harvard | Webster's 2011, focus, Smart Define, viewed 23 September, 2026, <http://smartdefine.org/focus/definitions/2009051>. |
| MLA | Webster's. "focus" 27 May 2011. Web. 23 September 2026. <http://smartdefine.org/focus/definitions/2009051> |