ETYM Colloq. U. S.
1. To make a deep hollow sound; SYN. boom out.
2. To make a resonant sound; as of artillery; SYN. din.
3. To grow stronger; SYN. prosper, thrive, get ahead, flourish, expand.
ETYM Old Eng. romblen, akin to Dutch rommelen, German rumpeln, Dan. rumle; cf. Icel. rymja to roar.
1. To make a low heavy rolling sound.
2. To travel with a low reverberating sound.
3. To speak in a low rolling tone.
4. To engage in a rumble.
5. To make a low noise, as of thunder; SYN. grumble.
6. To utter or emit in a low rolling voice.
7. (British) To reveal or discover the true character of.