The third axis used to locate points in three-dimensional space.

The z-coordinate of a point is the third element of the ordered triplet of a point in three-dimensional space that represents its position on the third axis of a Cartesian coordinate system in space.

### Example

In this illustration, the Cartesian coordinates of point *P* are (1, 3, 2). That is, its *x*-coordinate is 1, its *y*-coordinate is 3 and its *z*-coordinate is 2.