SECTOR • DICTIONARY ONE.COM • Definition of Sector

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/sˈɛktər/ Listen

noun

Sector n.

(Geom.) A part of a circle comprehended between two radii and the included arc.

A mathematical instrument, consisting of two rulers connected at one end by a joint, each arm marked with several scales, as of equal parts, chords, sines, tangents, etc., one scale of each kind on each arm, and all on lines radiating from the common center of motion. The sector is used for plotting, etc., to any scale.

An astronomical instrument, the limb of which embraces a small portion only of a circle, used for measuring differences of declination too great for the compass of a micrometer. When it is used for measuring zenith distances of stars, it is called a zenith sector.

Dip sector, an instrument used for measuring the dip of the horizon.

Sector of a sphere, or Spherical sector, the solid generated by the revolution of the sector of a circle about one of its radii, or, more rarely, about any straight line drawn in the plane of the sector through its vertex.

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Etymology of 'Sector'

Collaborative International Dictionary of English 0.48

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"Sector" Quotes from Famous Books

... place had been gutted by the latter's executors. In 1721 he got a transit instrument, and in 1726 a mural quadrant by Graham. His successor in 1742, Bradley, replaced this by a fine brass quadrant, eight feet radius, by Bird; and Bradley's zenith sector was purchased for the observatory. An instrument like this, specially designed for zenith stars, is capable of greater rigidity than a more universal instrument; and there is no trouble with refraction in the zenith. ...

— History of Astronomy • George Forbes

... system of wheels. An axle, set in motion by the latter, revolves one way or the other, according to the direction of the telescope's motions. This axle is provided with an endless screw that gears with a toothed sector, and the latter controls the rotatory axis of the alidade. The elements of the toothed wheels and the number of revolutions of the armature for a given displacement of the telescope being properly calculated, it will be seen that the alidade will be able to follow ...

— Scientific American Supplement, No. 363, December 16, 1882 • Various

... battalion waited with ever-growing impatience for the order that would send them "up the line," a group of officers was gathered in the senior major's hut for the purpose of studying in detail some photographs, secured by our aircraft, of the enemy trenches immediately opposite their own sector of the front line. They had finished their study, and were engaged in the diverting and pleasant exercise of ragging each other. The particular subject of that discussion was their various sprinting abilities, and the comparative usefulness of various kinds of funk-holes as a protection against ...

— The Sky Pilot in No Man's Land • Ralph Connor

... latter act, through an anchor escapement, upon a system of wheels. An axle, set in motion by the latter, revolves one way or the other, according to the direction of the telescope's motions. This axle is provided with an endless screw that gears with a toothed sector, and the latter controls the rotatory axis of the alidade. The elements of the toothed wheels and the number of revolutions of the armature for a given displacement of the telescope being properly calculated, it will be seen that the alidade will be able to follow ...

— Scientific American Supplement, No. 363, December 16, 1882 • Various

... "This is an important election Daddy! How could you possibly relax? There're seventy-three seats in question ... the whole balance. If things go wrong in just the Alkes sector ... why ... you could be sent back to the floor. You'd lose your job as ... why ... someone else ...

— Operation Haystack • Frank Patrick Herbert

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