Webster's Revised Unabridged Dictionary · 1913

Quadratic

Quadratic , adjective

[Compare French quadratique.]

1.
Of or pertaining to a square, or to squares; resembling a quadrate, or square; square.
2.
(Crystallography) Tetragonal.
3.
(Algebra) Pertaining to terms of the second degree; as, a quadratic equation, in which the highest power of the unknown quantity is a square.