Longitudinal Wave

A wave in which the vibrations of the medium are parallel to the direction the wave is moving.

Sound waves propagating through air are a good example.

In longitudinal waves, such as sound waves, wavelength is the distance from rarefaction to rarefaction, or compression to compression.

See also: Compressional Wave, Cylindrical Wave, Plane Wave, Rayleigh Waves, Shear Wave, Sound Waves, Spherical Wave, Transverse Wave, Wave.