focus: Meaning and Definition of

fo•cus

1. a central point, as of attraction, attention, or activity: The need to prevent a nuclear war became the focus of all diplomatic efforts.
2. a point at which rays of light, heat, or other radiation, meet after being refracted or reflected.
3. in focus; out of focus.
1. the focal point of a lens.
2. the focal length of a lens.
3. the clear and sharply defined condition of an image.
4. the position of a viewed object or the adjustment of an optical device necessary to produce a clear image:in focus; out of focus.
4. (of a conic section) a point having the property that the distances from any point on a curve to it and to a fixed line have a constant ratio for all points on the curve. See diag. under
5. the point of origin of an earthquake.
6. the primary center from which a disease develops or in which it localizes.

1. to bring to a focus or into focus: to focus the lens of a camera.
2. to concentrate: to focus one's thoughts.

1. to become focused.