May refer to an electromagnetic wave (such as a radio wave) or the PCB manufacturing process of wave soldering.
Radiation of the electromagnetic spectrum (sound, light, radio, microwave, etc.) typically propagates as waves (and/or particles).
"Wave soldering" is a manufacturing process in which a PCB populated with components is positioned slightly above the surface of molten solder in a container. An actuator then introduces mechanical motion such that the surface of the solder has a ripple (or wave) which extends upward to the PCB surface, soldering component leads in place.