Quad*rat"ic (?), a. [Cf. F.
quadratique.]
1. Of or pertaining to a square, or to
squares; resembling a quadrate, or square; square.
2. (Crystallog.) Tetragonal.
3. (Alg.) Pertaining to terms of the
second degree; as, a quadratic equation, in which the highest
power of the unknown quantity is a square.