Period, \(T\), is defined as the amount of time it takes to go around once - the time to cover an angle of \(2\pi\) radians.

Frequency, \(f\), is defined as the rate of rotation, or the number of rotations in some unit of time.

Angular frequency, \(\omega\), is the rotation rate measured in radians.

These three quantities are related by \(f=\frac{1}{T}=\frac{\omega}{2\pi}\).

The speed at which an object goes around a circle can be related to these quantities through \(v=R \omega=\frac{2\pi R}{T}\).