Merriam-Webster's Collegiate® Dictionary, 11th Edition
RUMBLE
I. verb (rumbled; rumbling)
Etymology: Middle English; akin to Middle High German rummeln to rumble
Date: 14th century
intransitive verb to make a low heavy rolling sound , to travel with a low re verb erating sound , to speak in a low rolling tone, to engage in a rumble, transitive verb to utter or emit in a low rolling voice, to reveal or discover the true character of, rumbler noun
II. noun
Date: 14th century
1. a low heavy continuous re verb erating often muffled sound (as of thunder), low frequency noise in phonographic playback caused by the transmission of mechanical vibrations by the turntable to the pickup, a seat for servants behind the body of a carriage,
3. widespread expression of dissatisfaction or unrest, a street fight especially among gangs