A wave that interferes with its own reflection so as to produce oscillations which stand still, rather than traveling down the length of the medium. Standing waves on a string with both ends tied down make up the harmonic series.
The appearance that the sound wave from a pure tone is not moving anywhere. It produces spots where the pure tone is loud (called a lobe) and other spots where the same tone cannot be heard at all ( this is a null). These spots will occur at distances of only a few inches to a few feet apart, depending on the wavelength of the tone. It will be difficult to tell the direction that these tones are coming from because these waves are not moving.
Continual waves which remain in one place; usually caused by the dissipation of energy when a fast flowing current reaches a slower pool of water or by obstructions.