quad·ric /ˈkwɑdrɪk/
  (a.)二次的二次曲面
  quadric
  二次的; 二次曲面的
  quadric
  二次 二次曲面
  Quad·ric a. Math. Of or pertaining to the second degree.
  Quad·ric, n. (a) Alg. A quantic of the second degree. See Quantic. (b) Geom. A surface whose equation in three variables is of the second degree. Spheres, spheroids, ellipsoids, paraboloids, hyperboloids, also cones and cylinders with circular bases, are quadrics.
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  quadric
       n : a curve or surface whose equation (in Cartesian coordinates)
           is of the second degree [syn: quadric surface]