sector

sector
    n 1: a plane figure bounded by two radii and the included arc of
         a circle
    2: a social group that forms part of the society or the economy;
       "the public sector"
    3: a particular aspect of life or activity; "he was helpless in
       an important sector of his life" [syn: {sector}, {sphere}]
    4: the minimum track length that can be assigned to store
       information; unless otherwise specified a sector of data
       consists of 512 bytes
    5: a portion of a military position
    6: measuring instrument consisting of two graduated arms hinged
       at one end
    

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]
    

36 Moby Thesaurus words for "sector":
      adjunct, component, contingent, crescent, cross section,
      detachment, detail, district, division, dole, fraction,
      half circle, hemicycle, installment, item, parcel, part,
      particular, percentage, portion, precinct, quadrant, quarter,
      quota, random sample, remainder, sample, sampling, section,
      segment, semicircle, sextant, share, subdivision, subgroup,
      subspecies