late 14c., resownen, "re-echo, return an echo; reverberate with," from Old French resoner "reverberate" (12c., Modern French résonner), from Latin resonare "sound again, resound, echo," from re- "back, again" (see re-) + sonare "to sound, make a noise," "to sound," from PIE *swene-, from root *swen- "to sound." Spelling influenced from mid-15c. by sound (v.). Related: Resounded; resounding.