Definition:Polar Coordinates/Angular Coordinate

Definition

Let $P$ be a point in a system of polar coordinates where $O$ is the pole.

The angle measured anticlockwise from the polar axis to $OP$ is called the angular coordinate of $P$, and usually labelled $\theta$.

If the angle is measured clockwise from the polar axis to $OP$, its value is considered negative.

The angular coordinate in a system of polar coordinates is also known as the polar angle, or azimuth.

Other words that can be seen to mean the same thing are:

Beware the term azimuth, as it is used in astronomy in a similar but significantly different way, to mean the angle measured from the principal vertical circle.