thrum

a monotonous sound like that of an insect in motion the steady thrum of the turbines in the power plant Synonyms burr, buzz, chirr, churr, drone, purr, hum, whir (also whirr), whiz (or whizz), zoomRelated Words babble, coo, gasp, gurgle, hiss, moan, murmur, rustle, sigh, suspiration, susurration, susurrus, whisper; whish, zing, zipNear Antonyms bawl, howl, roar, scream, screech, shriek, squall, squeal, yelp, yell