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.

• 象限在笛卡尔坐标系中，被坐标轴分开的平面中的四个区域的任一个，命名为第一，第二，第三和第四，从此象限逆时针计算坐标为正数