Encyclopedia
Wave
Disturbance propagating at a certain speed through an elastic medium such that, at each point of the medium, the quantity selected as a measure of disturbance is a function of time, and at any given moment, the same quantity is a function of the position of the point [IEC 50 (801)]
Source: "STATE SYSTEM FOR ENSURING UNIFORMITY OF MEASUREMENTS. HYDROACOUSTIC MEASUREMENTS. TERMS AND DEFINITIONS. GOST R 50.2.037-2004"
(approved by the Decree of Gosstandart Russia dated 11.02.2004 No. 55-st)