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.