The time taken by two consecutive compressions or rarefactions to cross a fixed point is called the time period of the wave. It represents the duration of one complete oscillation of the sound wave.

Hertz (Hz) is the unit used to measure frequency and it represents the number of oscillations or cycles per second. For example, a frequency of 100 Hz means that there are 100 oscillations occurring per second.

Frequency is typically represented by the Greek letter ν (nu) and its SI unit is hertz (Hz).

One complete oscillation in terms of sound wave frequency is the change in density from the maximum value to the minimum value, and then back to the maximum value again.

Frequency can be likened to the number of times a drum is beaten in a given time period. If you beat a drum ten times in one minute, the frequency of your drumming is ten beats per minute.