quadric surface

In mathematics, a quadric, or quadric surface, is any D-dimensional hypersurface defined as the locus of zeros of a quadratic polynomial. In coordinates , the general quadric is defined by the algebraic equation where Q is a (D + 1)-dimensional  matrix and P is a (D + 1)-dimensional  vector and R a constant. The values Q, P and R are often taken to be real numbers or complex numbers, but in fact, a quadric may be defined over any ring. In general, the locus of zeros of a set of polynomials is known as an algebraic variety, and is studied in the branch of algebraic geometry.
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Noun
1. a curve or surface whose equation (in Cartesian coordinates) is of the second degree
(synonym) quadric
(hypernym) curve, curved shape
(hyponym) hyperboloid