1. （圆或其他形状的）四分之一;象限
A quadrant is one of four equal parts into which a circle or other shape has been divided.

1. a measuring instrument for measuring altitude of heavenly bodies

2. the area enclosed by two perpendicular radii of a circle

3. any of the four areas into which a plane is divided by two orthogonal coordinate axes

4. a quarter of the circumference of a circle

Synonym: quarter-circle