To cause to move backward and forward, or up and down, in undulations or waves; to cause to vibrate.

To move in, or have, undulations or waves; to vibrate; to wave; as, undulating air.

Furnished with wave-like markings

increase and decrease in volume or pitch, as if in waves; "The singer's voice undulated"

to cause to move in a wavelike motion. It is a regular rising and falling or movement to alternating sides. It is movement in waves.