foci plural
fo·ci
The plural form of foci is focus
F fDefinitions
- noun plural foci a central point, as of attraction, attention, or activity: The need to prevent a nuclear war became the focus of all diplomatic efforts. 1
- noun plural foci Physics. a point at which rays of light, heat, or other radiation meet after being refracted or reflected. 1
- noun plural foci Optics. the focal point of a lens, on which rays converge or from which they deviate. the focal length of a lens; the distance from a focal point to a corresponding principal plane. 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. 1
- noun plural foci Geometry. (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. 1
- noun plural foci Geology. the point of origin of an earthquake. 1
- noun plural foci Pathology. the primary center from which a disease develops or in which it localizes. 1