Adjacent Words

Quadrant definitions

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Webster's 1828 Dictionary

QUAD'RANT, n. [L. quadrans, a fourth.]
1. The fourth part; the quarter.
2. In geometry, the quarter of a circle; the arc of a circle containing ninety degrees; also, the space or area included between this arc and two radii drawn from the center to each extremity.
3. An instrument for taking the altitudes of the sun or stars, of great use in astronomy and navigation. Quadrants are variously made, but they all consist of the quarter of a circle whose limb is divided into ninety degrees; or, as in Hadley's reflecting quadrant, an arc of forty five degrees is made to serve the same purpose as an arc of ninety degrees.
Quadrant of altitude, an appendage of the artificial globe, consisting of a slip of brass of the length of a quadrant of one of the great circles of the globe, and graduated. It is filled to the meridian and movable round to all points of the horizon. It serves as a scale in measuring altitudes, azimuths, etc.

WordNet (r) 3.0 (2005)

n
1: a quarter of the circumference of a circle [syn: quadrant, quarter-circle]
2: any of the four areas into which a plane is divided by two orthogonal coordinate axes
3: the area enclosed by two perpendicular radii of a circle
4: a measuring instrument for measuring altitude of heavenly bodies

Merriam Webster's

noun Etymology: Middle English, from Latin quadrant-, quadrans fourth part; akin to Latin quattuor four — more at four Date: 15th century 1. a. an instrument for measuring altitudes consisting commonly of a graduated arc of 90 degrees with an index or vernier and usually having a plumb line or spirit level for fixing the vertical or horizontal direction b. a device or mechanical part shaped like or suggestive of the quadrant of a circle 2. a. an arc of 90 degrees that is one quarter of a circle b. the area bounded by a quadrant and two radii 3. a. any of the four parts into which a plane is divided by rectangular coordinate axes lying in that plane b. any of the four quarters into which something is divided by two real or imaginary lines that intersect each other at right angles • quadrantal adjective

Oxford Reference Dictionary

n. 1 a quarter of a circle's circumference. 2 a plane figure enclosed by two radii of a circle at right angles and the arc cut off by them. 3 a quarter of a sphere etc. 4 a a thing, esp. a graduated strip of metal, shaped like a quarter-circle. b an instrument graduated (esp. through an arc of 90°) for taking angular measurements. Derivatives: quadrantal adj. Etymology: ME f. L quadrans -antis quarter f. quattuor four

Webster's 1913 Dictionary

Quadrant Quad"rant, n. [L. quadrans, -antis, a fourth part, a fourth of a whole, fr. quattuor four: cf. F. quadrant, cadran. See Four, and cf. Cadrans.] 1. The fourth part; the quarter. [Obs.] --Sir T. Browne. 2. (Geom.) The quarter of a circle, or of the circumference of a circle, an arc of 90[deg], or one subtending a right angle at the center. 3. (Anal. (Geom.) One of the four parts into which a plane is divided by the co["o]rdinate axes. The upper right-hand part is the first quadrant; the upper left-hand part the second; the lower left-hand part the third; and the lower right-hand part the fourth quadrant. 4. An instrument for measuring altitudes, variously constructed and mounted for different specific uses in astronomy, surveying, gunnery, etc., consisting commonly of a graduated arc of 90[deg], with an index or vernier, and either plain or telescopic sights, and usually having a plumb line or spirit level for fixing the vertical or horizontal direction. Gunner's quadrant, an instrument consisting of a graduated limb, with a plumb line or spirit level, and an arm by which it is applied to a cannon or mortar in adjusting it to the elevation required for attaining the desired range. Gunter's quadrant. See Gunter's quadrant, in the Vocabulary. Hadley's quadrant, a hand instrument used chiefly at sea to measure the altitude of the sun or other celestial body in ascertaining the vessel's position. It consists of a frame in the form of an octant having a graduated scale upon its arc, and an index arm, or alidade pivoted at its apex. Mirrors, called the index glass and the horizon glass, are fixed one upon the index arm and the other upon one side of the frame, respectively. When the instrument is held upright, the index arm may be swung so that the index glass will reflect an image of the sun upon the horizon glass, and when the reflected image of the sun coincides, to the observer's eye, with the horizon as seen directly through an opening at the side of the horizon glass, the index shows the sun's altitude upon the scale; -- more properly, but less commonly, called an octant. Quadrant of altitude, an appendage of the artificial globe, consisting of a slip of brass of the length of a quadrant of one of the great circles of the globe, and graduated. It may be fitted to the meridian, and being movable round to all points of the horizon, serves as a scale in measuring altitudes, azimuths, etc.

Collin's Cobuild Dictionary

(quadrants) A quadrant is one of four equal parts into which a circle or other shape has been divided. A symbol appears in an upper quadrant of the screen. N-COUNT: usu with supp, adj N, N of n

Moby Thesaurus

adjunct, astrolabe, azimuth circle, azimuth compass, bevel, bevel protractor, bevel square, clinometer, component, contingent, crescent, cross section, detachment, detail, division, dole, fraction, goniometer, graphometer, half circle, hemicycle, installment, item, pantometer, parcel, part, particular, percentage, portion, protractor, quarter, quota, radiogoniometer, random sample, remainder, sample, sampling, section, sector, segment, semicircle, sextant, share, subdivision, subgroup, subspecies, theodolite, transit, transit circle, transit instrument, transit theodolite