Quadrant
Definition of Quadrant
Quad´rant | n. | 1. | The fourth part; the quarter. | | 2. | (Geom.) The quarter of a circle, or of the circumference of a circle, an arc of 90°, 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 coördinate 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°, 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.| 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. |
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Related Words
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
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Quack
Quack grass
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Quadragesima Sunday
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-Quadrant-
Quadrant of altitude
Quadrantal
Quadrantal triangle
Quadrantal versor
Quadrat
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Quadrate bone
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Quadratojugal
Quadratojugal bone
Quadratrix
Quadrature
Quadrature of an orbit
Quadrature of the moon
Quadrel
Quadrennial
Quadrennially
Quadrennium
Quadri-
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