Quadrant

• POS: Noun
• HYPHEN: quad=rant

CIDE DICTIONARY

Quadrant, n. [L. quadrans, -antis, a fourth part, a fourth of a whole, fr. quattuor four: cf. F. quadrant, cadran. See Four, and cf. Cadrans.].

•  The fourth part; the quarter.  Sir T. Browne.  [1913 Webster]
•  The quarter of a circle, or of the circumference of a circle, an arc of 901913 Webster]
•  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.  [1913 Webster]
•  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 901913 Webster]

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.

OXFORD DICTIONARY

Quadrant, 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.

Derivative

quadrantal adj.

Etymology

ME f. L quadrans -antis quarter f. quattuor four

THESAURUS

Quadrant

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

ROGET THESAURUS

Quadrant

Quadrisection

N quadrisection, quadripartition, quartering, fourth, quart, quarter, quartern, farthing, fourthing, quadrant, quartered, quadrifid, quadripartite, rectangular.

Angularity

N angularity, angularness, aduncity, angle, cusp, bend, fold, notch, fork, bifurcation, elbow, knee, knuckle, ankle, groin, crotch, crutch, crane, fluke, scythe, sickle, zigzag, kimbo, akimbo, corner, nook, recess, niche, oriel, coign, right angle, obliquity, angle of 45 degrees, miter, acute angle, obtuse angle, salient angle, reentering angle, spherical angle, angular measurement, angular elevation, angular distance, angular velocity, trigonometry, goniometry, altimetry, clinometer, graphometer, goniometer, theodolite, sextant, quadrant, dichotomy, triangle, trigon, wedge, rectangle, square, lozenge, diamond, rhomb, rhombus, quadrangle, quadrilateral, parallelogram, quadrature, polygon, pentagon, hexagon, heptagon, octagon, oxygon, decagon, pyramid, cone, Platonic bodies, cube, rhomboid, tetrahedron, pentahedron, hexahedron, octahedron, dodecahedron, icosahedron, eicosahedron, prism, pyramid, parallelopiped, curb roof, gambrel roof, mansard roof, angular, bent, crooked, aduncous, uncinated, aquiline, jagged, serrated, falciform, falcated, furcated, forked, bifurcate, zigzag, furcular, hooked, dovetailed, knock kneed, crinkled, akimbo, kimbo, geniculated, oblique, fusiform, wedge-shaped, cuneiform, cuneate, multangular, oxygonal, triangular, trigonal, trilateral, quadrangular, quadrilateral, foursquare, rectangular, square, multilateral, polygonal, cubical, rhomboid, rhomboidal, pyramidal.

Circularity

N circularity, roundness, rotundity, circle, circlet, ring, areola, hoop, roundlet, annulus, annulet, bracelet, armlet, ringlet, eye, loop, wheel, cycle, orb, orbit, rundle, zone, belt, cordon, band, contrate wheel, crown wheel, hub, nave, sash, girdle, cestus, cincture, baldric, fillet, fascia, wreath, garland, crown, corona, coronet, chaplet, snood, necklace, collar, noose, lasso, lassoo, ellipse, oval, ovule, ellipsoid, cycloid, epicycloid, epicycle, semicircle, quadrant, sextant, sector, sphere, round, rounded, circular, annular, orbicular, oval, ovate, elliptic, elliptical, egg-shaped, pear-shaped, cycloidal, spherical, I watched the little circles die.