﻿ Definition of focus. Meaning of focus. Synonyms of focus

# Definition of focus. Meaning of focus. Synonyms of focus

Here you will find one or more explanations in English for the word focus. Also in the bottom left of the page several parts of wikipedia pages related to the word focus and, of course, focus synonyms and on the right images related to the word focus.

## Definition of focus

Focus
Focus Fo"cus, n.; pl. E. Focuses, L. Foci. [L. focus hearth, fireplace; perh. akin to E. bake. Cf. Curfew, Fuel, Fusil the firearm.] 1. (Opt.) 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. 2. (Geom.) 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. Note: Thus, in the ellipse FGHKLM, A is the focus and CD the directrix, when the ratios FA:FE, GA:GD, MA:MC, etc., are all equal. So in the hyperbola, A is the focus and CD the directrix when the ratio HA:HK is constant for all points of the curve; and in the parabola, A is the focus and CD the directrix when the ratio BA:BC is constant. In the ellipse this ratio is less than unity, in the parabola equal to unity, and in the hyperbola greater than unity. The ellipse and hyperbola have each two foci, and two corresponding directrixes, and the parabola has one focus and one directrix. In the ellipse the sum of the two lines from any point of the curve to the two foci is constant; that is: AG+GB=AH+HB; and in the hyperbola the difference of the corresponding lines is constant. The diameter which passes through the foci of the ellipse is the major axis. The diameter which being produced passes through the foci of the hyperbola is the transverse axis. The middle point of the major or the transverse axis is the center of the curve. Certain other curves, as the lemniscate and the Cartesian ovals, have points called foci, possessing properties similar to those of the foci of conic sections. In an ellipse, rays of light coming from one focus, and reflected from the curve, proceed in lines directed toward the other; in an hyperbola, in lines directed from the other; in a parabola, rays from the focus, after reflection at the curve, proceed in lines parallel to the axis. Thus rays from A in the ellipse are reflected to B; rays from A in the hyperbola are reflected toward L and M away from B. 3. A central point; a point of concentration. Aplanatic focus. (Opt.) See under Aplanatic. Conjugate focus (Opt.), the focus for rays which have a sensible divergence, as from a near object; -- so called because the positions of the object and its image are interchangeable. Focus tube (Phys.), a vacuum tube for R[oe]ntgen rays in which the cathode rays are focused upon the anticathode, for intensifying the effect. Principal, or Solar, focus (Opt.), the focus for parallel rays.
focus
Focus Fo"cus, n.; pl. E. Focuses, L. Foci. [L. focus hearth, fireplace; perh. akin to E. bake. Cf. Curfew, Fuel, Fusil the firearm.] 1. (Opt.) 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. 2. (Geom.) 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. Note: Thus, in the ellipse FGHKLM, A is the focus and CD the directrix, when the ratios FA:FE, GA:GD, MA:MC, etc., are all equal. So in the hyperbola, A is the focus and CD the directrix when the ratio HA:HK is constant for all points of the curve; and in the parabola, A is the focus and CD the directrix when the ratio BA:BC is constant. In the ellipse this ratio is less than unity, in the parabola equal to unity, and in the hyperbola greater than unity. The ellipse and hyperbola have each two foci, and two corresponding directrixes, and the parabola has one focus and one directrix. In the ellipse the sum of the two lines from any point of the curve to the two foci is constant; that is: AG+GB=AH+HB; and in the hyperbola the difference of the corresponding lines is constant. The diameter which passes through the foci of the ellipse is the major axis. The diameter which being produced passes through the foci of the hyperbola is the transverse axis. The middle point of the major or the transverse axis is the center of the curve. Certain other curves, as the lemniscate and the Cartesian ovals, have points called foci, possessing properties similar to those of the foci of conic sections. In an ellipse, rays of light coming from one focus, and reflected from the curve, proceed in lines directed toward the other; in an hyperbola, in lines directed from the other; in a parabola, rays from the focus, after reflection at the curve, proceed in lines parallel to the axis. Thus rays from A in the ellipse are reflected to B; rays from A in the hyperbola are reflected toward L and M away from B. 3. A central point; a point of concentration. Aplanatic focus. (Opt.) See under Aplanatic. Conjugate focus (Opt.), the focus for rays which have a sensible divergence, as from a near object; -- so called because the positions of the object and its image are interchangeable. Focus tube (Phys.), a vacuum tube for R[oe]ntgen rays in which the cathode rays are focused upon the anticathode, for intensifying the effect. Principal, or Solar, focus (Opt.), the focus for parallel rays.
Focus
Focus Fo"cus, v. t. [imp. & p. p. Focused; p. pr. & vb. n. Focusing.] To bring to a focus; to focalize; as, to focus a camera. --R. Hunt.

## Meaning of focu from wikipedia

- was quickly abandoned, and parton more or less focu(s)sed on recording country material for the remainder of her association with the label.
- focu, his first comic book hero, was created in 1993 and quickly became the mascot of xl magazine. focu is a hypocrite who cannot resist
- focum , fogu , fuoco , focu , focu , foc , fûc , feu , fieu , feu , fuòc , foc , fuego , fuego , huego , fueu , fuogo , fogo , fogo ,
- references : com/2002/03/14/technology/circuits/14focu. html? ex 1131944400&en 8c09e64bdface973&ei 5070 yudhijit bhattacharjee. in a seamless
- at exactly midnight the ‘camejuzzu i focu’ dance is performed. the traditional fireworks display closes the festival. ' 'ice-cream festival
- dhc-2 beaver , 13 , mk 1 , fius, fjac, fjgv, fjki, fkrj, focu, fuwj, fyyt, gaef, gaxl, gpuo, guji, gwae , dhc-3 otter , 12 , , fazw, fdak
- a li fìmmini nostri ci scipparu di l’occhi la lustrura e lu focu ca addumava li specchi. n’arrubbaru lu suli, lu suli arristamu a lu scuru,
- track listing : focu di raggia. me sam devla romani. koferi. bijav. lamour. references : category:2007 albums category:goran bregović albums
- laudato si, mi signore, per frate focu,per lo quale ennallumini la nocte:ed ello è bello et iucundo et robustoso et forte. laudato si, mi
- discography : 2010 – focu d'amore. 2012 it , pizzica indiavolata awards and nominations : 2010 – best italian world music band – mei's confab