For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics, acoustics, and radio, frequency is usually denoted by a Latin letter f or by the Greek letter ν (\ displaystyle \ nu) or ν (nu) (see e.g. Planck 's formula).
give the definition of the frequency of a wave
a number of cycles per unit time