The distance from one point on a wave to the same next wave is called the wavelength. It is the measure of the spatial period of a wave—the distance over which the wave's shape repeats. Wavelength is usually measured in meters, centimeters, or millimeters.

The wavelength of a wave is related to its frequency and wave speed by the following equation:

wavelength = wave speed / frequency

where:

- wavelength is the distance from one point on a wave to the same next wave

- wave speed is the speed at which the wave travels

- frequency is the number of waves that pass a given point in one second

The wavelength of a wave can also be determined by measuring the distance between two adjacent peaks or troughs of the wave.