thrumverb
/θrʌm/-mm-[ I ] to make a continuous low sound:
The engine was thrumming steadily.
[ T ] to play a guitar or similar stringed instrument in a way that makes a rhythm:
He can thrum a guitar, but he's not Jimmy Hendrix.
thrumnoun [ S ]
/θrʌm/a continuous low sound:
the steady thrum of horses galloping