sec·tor /ˈsɛktɚ/
 扇形,尺規,函數尺(vt.)把…分成扇形


 sector
 區( 段 ); 段 S;SCT


 sector
 扇區


 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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 sector
      n 1: a plane figure bounded by two radii and the included arc of
           a circle
      2: a body of people who form part of society or economy; "the
         public sector"
      3: a particular aspect of life or activity; "he was helpless in
         an important sector of his life" [syn: 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