*Cartesian coordinates* are the familiar \((x,y)\) coordinates in two dimensions and \((x,y,z)\) coordinates in three dimensions.

They describe any point on a plane using two numbers, and any point in space using three numbers, using a set of two or three axes at right angles to one another and measuring along these axes. It is named after René Descartes (1596–1650), who invented it while thinking about how to describe problems in geometry using the language of algebra.