ETYM Latin quadrans, -antis, a fourth part, a fourth of a whole, from quattuor four: cf. French quadrant, cadran. Related to Four, Cadrans.
1. A quarter of the circumference of a circle; SYN. quarter-circle, right angle.
2. An instrument for measuring altitude of heavenly bodies.
3. Any of the four areas into which a plane is divided by two orthogonal coordinate axes.
4. The area enclosed by two perpendicular radii of a circle.
Quarter of circumference of circle; instrument for measuring altitudes.