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noun fo·cus \ˈfō-kəs\

Simple Definition of focus

  • : 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.

Source: Merriam-Webster's Learner's Dictionary

Full Definition of focus

plural foci play \ˈfō-ˌsī also -ˌkī\ also focuses

  1. 1 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)

  2. 2 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>

  3. 3 :  one of the fixed points that with the corresponding directrix defines a conic section

  4. 4 :  a localized area of disease or the chief site of a generalized disease or infection

  5. 5 a :  a center of activity, attraction, or attention <the focus of the meeting was drug abuse> b :  a point of concentration

  6. 6 :  the place of origin of an earthquake or moonquake

  7. 7 :  directed attention :  emphasis

focusless play \-ləs\ adjective
in focus
  1. :  having or giving the proper sharpness of outline due to good focusing

out of focus
  1. :  not in focus

Examples of focus in a sentence

  1. He's successful, but he feels that his life lacks focus.

  2. His life lacks a focus.

Origin of focus

New Latin, from Latin, hearth

First Known Use: 1644

Other Pictures (on film) Terms

Rhymes with focus



verb fo·cus

Simple Definition of focus

  • : 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

Source: Merriam-Webster's Learner's Dictionary

Full Definition of focus

focused also focussedfocusing also focussing

  1. transitive verb
  2. 1 a :  to bring into focus b :  to adjust the focus of (as the eye or a lens)

  3. 2 :  to cause to be concentrated <focused their attention on the most urgent problems>

  4. 3 :  to bring (as light rays) to a focus :  concentrate

  5. intransitive verb
  6. 1 :  to come to a focus :  converge

  7. 2 :  to adjust one's eye or a camera to a particular range

  8. 3 :  to concentrate attention or effort

focusable play \-kə-sə-bəl\ adjective
focuser noun

Examples of focus in a sentence

  1. She has an amazing ability to focus for hours at a time.

  2. I wasn't able to focus the camera.

  3. I wasn't able to get the camera to focus.


First Known Use of focus


FOCUS Defined for Kids



noun fo·cus \ˈfō-kəs\

Definition of focus for Students

plural fo·ci \ˈfō-ˌsī\ also fo·cus·es

  1. 1 :  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

  2. 2 :  the distance from a lens or mirror to a focus

  3. 3 :  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>

  4. 4 :  a center of activity or interest <Fractions are the focus of this lesson.>

History for 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.



verb fo·cus

Definition of focus for Students

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

  1. 1 :  to bring or come to a focus <focus rays of light>

  2. 2 :  to adjust the focus of <He focused his binoculars.>

  3. 3 :  to direct or cause to direct at <Focus your attention here.>

Seen and Heard

What made you want to look up focus? Please tell us where you read or heard it (including the quote, if possible).


to defraud especially of money

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