Wavelength is: (1) The wavelength of a wave is the distance (parallel to the direction of wave propagation) between the consecutive repetitions of the shape of the wave. It is the minimum distance between two consecutive points in the same phase of wave motion. (2) The distance between two consecutive compressions (C) or two consecutive rarefactions (R) is called the Wavelength. The Wavelength is usually represented by λ (Greek Letter Lambda).