Pronunciation: (fō'kus), [key]
— n., pl. v., -cus•es, -ci -cused, -cus•ing -cussed, -cus•sing.
- a central point, as of attraction, attention, or activity: The need to prevent a nuclear war became the focus of all diplomatic efforts.
- a point at which rays of light, heat, or other radiation, meet after being refracted or reflected.
- in focus; out of focus.
- the focal point of a lens.
- the focal length of a lens.
- the clear and sharply defined condition of an image.
- the position of a viewed object or the adjustment of an optical device necessary to produce a clear image:in focus; out of focus.
- (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
- the point of origin of an earthquake.
- the primary center from which a disease develops or in which it localizes.
- to bring to a focus or into focus: to focus the lens of a camera.
- to concentrate: to focus one's thoughts.
- to become focused.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.