period (of motion)

is in general: the time interval over which a repeating motion or event recurs. [M6.4]

is in particular: the time taken for an oscillating system to complete one full cycle (i.e. one complete oscillation). [P5.1, P5.4, P5.5]

therefore is: the reciprocal of the frequency: [P5.7, P6.1]

is also: times the reciprocal of the angular frequency: [M5.1, P5.7, P6.1]

is exemplified: by a particle of mass executing simple harmonic motion along the -axis, under the influence of a force where the period is given by

[P5.1]

is also exemplified: by an orbiting particle, where the period is the time taken to complete one orbit. [P2.6]

is also exemplified: by a (periodic) wave, where the period is the time required for one complete cycle of the wave (i.e. one complete oscillation at any fixed point on the path of the wave). [P5.6, P6.1]