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¹focus

noun fo·cus \ˈfō-kəs\

: a subject that is being discussed or studied : the subject on which people's attention is focused

: a main purpose or interest

: a point at which rays of light, heat, or sound meet or from which they move apart or appear to move apart; especially : the point at which an image is formed by a mirror, a lens, etc.

plural fo·ci \ˈfō-ˌsī also -ˌkī\ also fo·cus·es

Full Definition of FOCUS

a : a point at which rays (as of light, heat, or sound) converge or from which they diverge or appear to diverge; specifically : the point where the geometrical lines or their prolongations conforming to the rays diverging from or converging toward another point intersect and give rise to an image after reflection by a mirror or refraction by a lens or optical system

b : a point of convergence of a beam of particles (as electrons)

a : focal length

b : adjustment for distinct vision; also : the area that may be seen distinctly or resolved into a clear image

c : a state or condition permitting clear perception or understanding <tried to bring the issues into focus>

d : direction 6c <the team lost focus>

: one of the fixed points that with the corresponding directrix defines a conic section

: a localized area of disease or the chief site of a generalized disease or infection

a : a center of activity, attraction, or attention <the focus of the meeting was drug abuse>

b : a point of concentration

: the place of origin of an earthquake or moonquake

: directed attention : emphasis

— fo·cus·less \-ləs\ adjective

— in focus

: having or giving the proper sharpness of outline due to good focusing

— out of focus

: not in focus

See focus defined for English-language learners

See focus defined for kids

Origin of FOCUS

New Latin, from Latin, hearth

First Known Use: 1644

Related to FOCUS

Synonyms: axis, base, capital, central, core, cynosure, epicenter, eye, center, ground zero, heart, hub, locus, mecca, navel, nerve center, nexus, nucleus, omphalos, seat

Other Pictures (on film) Terms

daguerreotype, emulsion, fill, sepia, still, stop

Rhymes with FOCUS

crocus, hocus, locus

²focus

verb

: to cause (something, such as attention) to be directed at something specific

: to direct your attention or effort at something specific

: to adjust (something, such as a lens or a camera) to make an image clear

fo·cused also fo·cussedfo·cus·ing also fo·cus·sing

Full Definition of FOCUS

transitive verb

a : to bring into focus

b : to adjust the focus of (as the eye or a lens)

: to cause to be concentrated <focused their attention on the most urgent problems>

: to bring (as light rays) to a focus : concentrate

intransitive verb

: to come to a focus : converge

: to adjust one's eye or a camera to a particular range

: to concentrate attention or effort

— fo·cus·able \-kə-sə-bəl\ adjective

— fo·cus·er noun

See focus defined for English-language learners

First Known Use of FOCUS

1775

Related to FOCUS

Synonyms: center, fasten, concentrate, rivet, train

FOCUS Defined for Kids

¹focus

noun fo·cus \ˈfō-kəs\

plural fo·ci \ˈfō-ˌsī\ also fo·cus·es

Definition of FOCUS for Kids

: a point at which rays (as of light, heat, or sound) meet after being reflected or bent : the point at which an image is formed

: the distance from a lens or mirror to a focus

: an adjustment that gives clear vision <He turned his head almost upside down to get a more acute focus on her … — Jean Craighead George, Julie of the Wolves>

: a center of activity or interest <Fractions are the focus of this lesson.>

Word History of FOCUS

We usually associate the word focus with a sharp image, and hence with light, but the word was first applied to heat. Scientists in the 1600s chose the Latin word focus (meaning “fireplace, hearth”) for the point at which rays of sunlight gathered by a magnifying glass converge and cause something to catch fire. Because light as well as heat is directed by a lens, the expansion of the sense was quite natural.