focus

[Fo·cus]

Focus is something that camera lenses and sleepy students are always being asked to do. For cameras, it means finding a point where the subject is clear or "in focus." For students, it means paying attention.

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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.

Noun
maximum clarity or distinctness of an image rendered by an optical system; "in focus"; "out of focus"

Noun
maximum clarity or distinctness of an idea; "the controversy brought clearly into focus an important difference of opinion"

Noun
the concentration of attention or energy on something; "the focus of activity shifted to molecular biology"; "he had no direction in his life"

Noun
a fixed reference point on the concave side of a conic section

Noun
a point of convergence of light (or other radiation) or a point from which it diverges

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Noun
a central point or locus of an infection in an organism; "the focus of infection"

Noun
special emphasis attached to something; "the stress was more on accuracy than on speed"

Verb
put (an image) into focus; "Please focus the image; we cannot enjoy the movie"

Verb
become focussed or come into focus; "The light focused"

Verb
direct one''s attention on something; "Please focus on your studies and not on your hobbies"

Verb
bring into focus or alignment; to converge or cause to converge; of ideas or emotions

Verb
cause to converge on or toward a central point; "Focus the light on this image"

n.
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.

n.
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.

n.
A central point; a point of concentration.

v. t.
To bring to a focus; to focalize; as, to focus a camera.

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. &hand; 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'd2ntgen rays in which the cathode rays are focused upon the anticathode, for intensifying the effect. -- Principal, ∨ Solar, focus (Opt.), the focus for parallel rays.

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.

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.

To bring to a focus; to focalize; as, to focus a camera.

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Usage Examples

Democrats think the country works better with a strong middle class, real opportunities for poor people to work their way into it and a relentless focus on the future, with business and government working together to promote growth and broadly shared prosperity. We think 'we're all in this together' is a better philosophy than 'you're on your own.'

A successful economic development strategy must focus on improving the skills of the area's workforce, reducing the cost of doing business and making available the resources business needs to compete and thrive in today's global economy.

Barack Obama knows that to create an economy built to last, we need to focus on middle-class families. Families who stay up on Sunday nights pacing the floor, like my dad did, while their children, tucked in bed, dream big dreams. Families who aren't sure what Monday morning will bring, but who believe our nation's best days are still ahead.

After 1980, you never heard reference to space again. Surface, the most convincing evidence of the descent into materialism, became the focus of design. Space disappeared.

But you can't focus on things that matter if all you've been is asleep for forty years. Funny how sleep rhymes with sheep. You know.

As a governor, I am naturally inclined to focus on the domestic side of protecting the United States.

But then it hasn't really been a focus of our government to make us an educated people.

Misspelled Form

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Other Usage Examples

Clarity affords focus.

Be curious, learn and read as much as you can about food. Don't worry about making money. Focus on learning at various venues before you settle down for a steady position.

Congress, the press, and the bureaucracy too often focus on how much money or effort is spent, rather than whether the money or effort actually achieves the announced goal.

All that running around in my underwear put money in my pockets. I can focus on working in interesting movies without having to worry about supporting myself.

Don't dwell on what went wrong. Instead, focus on what to do next. Spend your energies on moving forward toward finding the answer.

As a rule, my focus is on classical music, but I love jazz. I love everything, actually.

Do you want to be an artist and a writer, or a wife and a lover? With kids, your focus changes. I don't want to go to PTA meetings.

Concentrate all your thoughts upon the work at hand. The sun's rays do not burn until brought to a focus.