wave

2.26  wave. Disturbance such that the quantity serving as a measure of the disturbance varies with position and time in a manner that at pairs of neighboring positions the disturbance is similar except for a time difference.

Annotation 1          Any physical quantity that has the same relationship to some independent variable (usually time) that a propagated disturbance has at a particular instant, with respect to space, may be called a traveling wave. For a traveling wave, the velocity of propagation of the disturbance is equal to the distance between neighboring positions divided by the time difference.

Annotation 2          See also 5.06 through 5.23.