n.one of the coordinates in a system of coordinates that locates a point on a plane or in space by its distance from two lines or three planes respectively; the two lines or the intersections of the three planes are the coordinate axes
N-PLURAL
a system of representing points in space in terms of their distance from a given origin measured along a set of mutually perpendicular axes. Written (x,y,z) with reference to three axes 笛卡儿坐标