Quadric a. : Of or pertaining to the second degree.

Quadric n. : A quantic of the second degree. See Quantic.

Quadric n. : 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.

Example:
How do you find the domain and range of a Quadric surface/contour map?

Taxonomy
quadric, quadric surfaces, normal form, quadric surface, special case, free encyclopedia, elliptic paraboloid, dimension D, non-degenerate, coefficients, non-singular, zeros, Euclidean space, projective transformation, Projective geometry, Euclidean plane, ellipsoid, hyperbolic paraboloid.

Defination from the web:
quadric may be defined over any ring. ... Iskovskikh, V.A. (2001), "Quadric", in Hazewinkel, Michiel, Encyclopaedia of Mathematics, Kluwer Academic Publishers, ISBN 978-1556080104 ...