**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.

© Webster 1913.