reverberationn.

reverberation (n.)late 14c., "reflection of light or heat," from Old French reverberacion "great flash of light; intense quality," from Medieval Latin reverberationem (nominative reverberatio), noun of action from past participle stem of Latin reverberare "beat back, strike back, repel, cause to rebound," from re- "back" (see re-) + verberare "to strike, to beat," from verber "whip, lash, rod," related to verbena "leaves and branches of laurel," from PIE *werb- "to turn, bend" (see warp (v.)). Sense of "an echo" is attested from 1620s.