sector of a sphere

1 definition found

sector of a sphere - Collaborative International Dictionary of English v.0.48 :

  Sector \Sec"tor\, n. [L., properly, a cutter, fr. secare,
     sectum, to cut: cf. F. secteur. See Section.]
     1. (Geom.) A part of a circle comprehended between two radii
        and the included arc.
        [1913 Webster]
  
     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.
        [1913 Webster]
  
     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.
        [1913 Webster]
  
     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.
        [1913 Webster]