| Quadratic 1. (a.) Of or pertaining to a square, or to squares; resembling a quadrate, or square; square. 2. (a.) Tetragonal. 3. (a.) Pertaining to terms of the second degree; as, a quadratic equation, in which the highest power of the unknown quantity is a square. Thesaurus Entries aboveboard, authentic, biquadratic, bona fide, cube-shaped, cubed, cubic, cubiform, cuboid, diced, fair and square, four, four-legged, four-rayed, genuine, good-faith, oblong, on the level, on the square, on the up-and-up, open, open and aboveboard, orthogonal, quadrangular, quadrate, quadratic, quadric, quadriform, quadrilateral, quadrinomial, quadrivalent, quadruped, quartic, quartile, quaternary, rectangular, rhombic, rhomboid, single-hearted, square, square-dealing, square-shooting, straight, straight-shooting, tetractinal, tetrad, tetragonal, tetrahedral, tetravalent, trapezohedral, trapezoid, up-and-up, veritable |