1769, from Latin raucus "hoarse" (also source of French rauque, Spanish ronco, Italian rauco), related to ravus "hoarse," from PIE echoic base *reu- "make hoarse cries" (source also of Sanskrit rayati "barks," ravati "roars;" Greek oryesthai "to howl, roar;" Latin racco "a roar;" Old Church Slavonic rjevo "I roar;" Lithuanian rėkti "roar;" Old English rarian "to wail, bellow"). Middle English had rauc in the same sense, from the same source.
