foci

[ foh-sahy, -kahy ]

/ ˈfoʊ saɪ, -kaɪ /

noun

a plural of focus.

Words nearby foci

focal segmental glomerulosclerosis, focal seizure, focal-plane shutter, focalize, foch, foci, focometer, focsani, focus, focus group, focus puller

Definition for foci (2 of 2)

focus

[ foh-kuhs ]

/ ˈfoʊ kəs /

noun, plural fo·cus·es, fo·ci [foh-sahy, -kahy] /ˈfoʊ saɪ, -kaɪ/.

a central point, as of attraction, attention, or activity: The need to prevent a nuclear war became the focus of all diplomatic efforts.

Physics. a point at which rays of light, heat, or other radiation meet after being refracted or reflected.

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.

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.

Geology. the point of origin of an earthquake.

Pathology. the primary center from which a disease develops or in which it localizes.

verb (used with object), fo·cused, fo·cus·ing or (especially British) fo·cussed, fo·cus·sing.

to bring to a focus or into focus; cause to converge on a perceived point: to focus the lens of a camera.

to concentrate: to focus one's thoughts; to focus troop deployment in the east.

verb (used without object), fo·cused, fo·cus·ing or (especially British) fo·cussed, fo·cus·sing.

to be or become focused: My eyes have trouble focusing on distant objects.

to direct one's attention or efforts: Students must focus in class.

Origin of focus

1635–45; < Latin: fireplace, hearth

SYNONYMS FOR focus

1 center, heart, core, nucleus.

SEE SYNONYMS FOR focus ON THESAURUS.COM

OTHER WORDS FROM focus

fo·cus·a·ble, adjective fo·cus·er, noun mis·fo·cus, verb, mis·fo·cused, mis·fo·cus·ing or (especially British) mis·fo·cussed, mis·fo·cus·sing. mis·fo·cused, adjective

mis·fo·cussed, adjective o·ver·fo·cus, verb (used with object), o·ver·fo·cused, o·ver·fo·cus·ing or (especially British) o·ver·fo·cussed, o·ver·fo·cus·sing. re·fo·cus, verb, re·fo·cused, re·fo·cus·ing or (especially British) re·fo·cussed, re·fo·cus·sing. self-fo·cused, adjective self-fo·cus·ing, adjective self-fo·cussed, adjective self-fo·cus·sing, adjective un·fo·cus·ing, adjective un·fo·cus·sing, adjective well-fo·cused, adjective well-fo·cussed, adjective

Example sentences from the Web for foci

The circle has one focus at the centre, an ellipse or hyperbola two foci equidistant from the centre.

Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 |Various
In the old times of Roman domination the encampments of the legions in the provinces had always proved to be foci of civilization.

History of the Conflict Between Religion and Science |John William Draper
But the orbits are elliptical, and the Sun holds a position in one of the foci of each ellipse.

Astrology |Sepharial
Their physicians were their great philosophers; their medical colleges were their foci of learning.

History of the Intellectual Development of Europe, Volume I (of 2) |John William Draper

The curve thus traced will be an ellipse having the pins at the two points which are called its foci.

A Text-Book of Astronomy |George C. Comstock

British Dictionary definitions for foci

focus

/ (ˈfəʊkəs) /

noun plural -cuses or -ci (-saɪ, -kaɪ, -kiː)

a point of convergence of light or other electromagnetic radiation, particles, sound waves, etc, or a point from which they appear to diverge

another name for focal point (def. 1), focal length

optics the state of an optical image when it is distinct and clearly defined or the state of an instrument producing this image the picture is in focus; the telescope is out of focus

a point upon which attention, activity, etc, is directed or concentrated

geometry a fixed reference point on the concave side of a conic section, used when defining its eccentricity

the point beneath the earth's surface at which an earthquake or underground nuclear explosion originates Compare epicentre

pathol the main site of an infection or a localized region of diseased tissue

verb -cuses, -cusing, -cused, -cusses, -cussing or -cussed

to bring or come to a focus or into focus

(tr often foll by on) to fix attention (on); concentrate

Derived forms of focus

focusable, adjective focuser, noun

Word Origin for focus

C17: via New Latin from Latin: hearth, fireplace

Medical definitions for foci

focus

[ fō′kəs ]

n. pl. fo•cus•es

A point at which rays of light or other radiation converge or from which they appear to diverge, as after refraction or reflection in an optical system. focal point

focal length

The distinctness or clarity of an image rendered by an optical system.

The state of maximum distinctness or clarity of such an image.

An apparatus used to adjust the focal length of an optical system in order to make an image distinct or clear.

The region of a localized bodily infection or disease.

v.

To cause light rays or other radiation to converge on or toward a central point; concentrate.

To render an object or image in clear outline or sharp detail by adjustment of one's vision or an optical device.

To adjust a lens or instrument to produce a clear image.

To converge on or toward a central point of focus; be focused.

Scientific definitions for foci

focus

[ fō′kəs ]

Plural focuses or foci (fō′sī′, fō′kī′)

The degree of clarity with which an eye or optical instrument produces an image.

See focal point.

A central point or region, such as the point at which an earthquake starts.

Mathematics A fixed point or one of a pair of fixed points used in generating a curve such as an ellipse, parabola, or hyperbola.

The region of a localized bodily infection or disease.

BROWSE DICTIONARY

Learning

foci

noun

Words nearby foci

Definition for foci (2 of 2)

noun, plural fo·cus·es, fo·ci [foh-sahy, -kahy] /ˈfoʊ saɪ, -kaɪ/.

verb (used with object), fo·cused, fo·cus·ing or (especially British) fo·cussed, fo·cus·sing.

verb (used without object), fo·cused, fo·cus·ing or (especially British) fo·cussed, fo·cus·sing.

Origin of focus

SYNONYMS FOR focus

OTHER WORDS FROM focus

Example sentences from the Web for foci

British Dictionary definitions for foci

noun plural -cuses or -ci (-saɪ, -kaɪ, -kiː)

verb -cuses, -cusing, -cused, -cusses, -cussing or -cussed

Derived forms of focus

Word Origin for focus

Medical definitions for foci

n. pl. fo•cus•es

v.

Scientific definitions for foci

Plural focuses or foci (fō′sī′, fō′kī′)

BROWSE DICTIONARY

Learning

foci

noun

Words nearby foci

Definition for foci (2 of 2)

noun, plural fo·cus·es, fo·ci [foh-sahy, -kahy] /ˈfoʊ saɪ, -kaɪ/.

verb (used with object), fo·cused, fo·cus·ing or (especially British) fo·cussed, fo·cus·sing.

verb (used without object), fo·cused, fo·cus·ing or (especially British) fo·cussed, fo·cus·sing.

Origin of focus

SYNONYMS FOR focus

OTHER WORDS FROM focus

Words related to foci

Example sentences from the Web for foci

British Dictionary definitions for foci

noun plural -cuses or -ci (-saɪ, -kaɪ, -kiː)

verb -cuses, -cusing, -cused, -cusses, -cussing or -cussed

Derived forms of focus

Word Origin for focus

Medical definitions for foci

n. pl. fo•cus•es

v.

Scientific definitions for foci

Plural focuses or foci (fō′sī′, fō′kī′)