(kwŏdʹrənt) noun. Abbr. quad. Mathematics. a. A circular arc of 90°; one fourth of the circumference of a circle. b. The plane area bounded by such an arc and two perpendicular radii. c. Any of the four areas into which a plane is divided by the reference axes in a Cartesian coordinate system, designated first, second, third, and fourth, counting counterclockwise from the area in which both coordinates are positive, kuadran
quadrant (kwŏdʹrənt) noun. I. quarter of circle, sukuan; 2. instrument for measuring angle up to 90", kuadran.