DICT.TW Dictionary Taiwan

 Sec·tor n.
 1. Geom. A part of a circle comprehended between two radii and the included arc.
 2. 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.
 3. 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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 Spher·ic·al Spher·ic a.
 1. Having the form of a sphere; like a sphere; globular; orbicular; as, a spherical body.
 2. Of or pertaining to a sphere.
 3. Of or pertaining to the heavenly orbs, or to the sphere or spheres in which, according to ancient astronomy and astrology, they were set.
    Knaves, thieves, and treachers by spherical predominance.   --Shak.
 Though the stars were suns, and overburned
 Their spheric limitations.   --Mrs. Browning.
 Spherical angle, Spherical coordinate, Spherical excess, etc. See under Angle, Coordinate, etc.
 Spherical geometry, that branch of geometry which treats of spherical magnitudes; the doctrine of the sphere, especially of the circles described on its surface.
 Spherical harmonic analysis. See under Harmonic, a.
 Spherical lune,portion of the surface of a sphere included between two great semicircles having a common diameter.
 Spherical opening, the magnitude of a solid angle. It is measured by the portion within the solid angle of the surface of any sphere whose center is the angular point.
 Spherical polygon,portion of the surface of a sphere bounded by the arcs of three or more great circles.
 Spherical projection, the projection of the circles of the sphere upon a plane. See Projection.
 Spherical sector. See under Sector.
 Spherical segment, the segment of a sphere. See under Segment.
 Spherical triangle,re on the surface of a sphere, bounded by the arcs of three great circles which intersect each other.
 Spherical trigonometry. See Trigonometry.
 -- Spher*ic*al*ly, adv. -- Spher*ic*al*ness, n.
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