Answer:
Wavelength
Step-by-step explanation:
The wavelength of a transverse wave (where the oscillation occurs perpendicular to the direction of propagation of the wave) is defined as the distance between two consecutive crests ot two consecutive troughs.
In a longitudinal wave, where the oscillation occurs parallel to the direction of propagation of the wave, the wavelength is defined as the distance between two consecutive compressions or between two consecutive rarefactions.
Other important definitions for a wave are:
- Frequency: the number of complete cycles per second
- Period: the time needed for one complete cycle to occur
- Amplitude: the distance between the equilibrium position and the maximum displacement of the wave