Period

The period $T$ is the time for one complete cycle:

$T = \frac{1}{f}$

where $f$ is the frequency in hertz.

Period can be measured by timing several oscillations and dividing by the number of cycles. This reduces timing errors.

For a wave: the period is the time between two successive crests (or troughs) passing a fixed point. For a pendulum: the period is one complete swing (out and back).