Definitions for "Cartesian coordinates"
Most often in the plane, but also in the higher dimension spaces, the Cartesian coordinates are defined by a number (2 in the plane) of perpendicular number lines - coordinate axes. A point is then defined by its projections on the axes. In the plane, points are defined by 2 such projections that are written as an ordered pair of real numbers, (x, y).
A system in which points on a plane are identified by an ordered pair of numbers, representing the distances to two or three perpendicular axes.
Coordinate system in which the location of points in space are given by reference to three orthogonal planes, called coordinate planes.