1. a quarter of the circumference of a circle • Syn: quarter-circle • Hypernyms: line 2. any of the four areas into which a plane is divided by two orthogonal coordinate axes • Hypernyms: area, country 3. the area enclosed by two perpendicular radii of a circle • Hypernyms: area, country 4. a measuring instrument for measuring altitude of heavenly bodies • Hypernyms: measuring instrument, measuring system, measuring device