An Etymological Dictionary of Astronomy and Astrophysics

The periodic and alternatively strengthening and weakening of two waves of similar frequencies when they interfere with one another. In particular, the soft and loud sounds created by the
interference of two sound waves of similar frequencies.

Etymology (EN): M.E. beten, from O.E. beaten, from P.Gmc. *bautan; IER *bhau- “to strike.”

Etymology (PE): Zaneš, noun from zan- present tense stem of zadan “to beat, strike” + -š verbal noun suffix. Zadan from Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- “to strike, hit, smite, kill” (jantar- “smiter”); cf.
Skt. han- “to strike, beat” (hantar- “smiter, killer”); Gk. theinein “to strike;” L. fendere “to strike, push;” Gmc. *gundjo “war, battle;” PIE *g^when- “to strike, kill.”