An octant is one of 8 parts of the two-dimensional Euclidean coordinate system.

Traditionally wind direction is given as one of the 8 octants (N, NE, E, SE, S, SW, W, NW) because that is more accurate than merely giving one of the 4 quadrants, and the wind vane typically does not have enough accuracy to bother with more precise indication.

Octant in three-dimensional space

An octant is one of the eight divisions of a Euclidean three-dimensional coordinate system. It is similar to the two-dimensional quadrant and the one-dimensional ray.

The n-dimensional generalization is the orthant.

Octant order

Usually, the octant with all three positive coordinates is referred to as the first octant. Nevertheless there is no generally used naming convention for the other seven octants.