Intransitive verb

to groan; to moan

Intransitive verb

to roar; to howl; to growl

Intransitive verb

to hum (engine, wind, etc.); to buzz; to whiz; to sough; to make a low, dull sound

Intransitive verb

to ooh and aah (in admiration)

Transitive verb

to sing in a strong, low voice (esp. traditional chant or recitation)

Intransitive verb

to be about to burst; to overflow

to moan; to groan

groan; moan; moaning

groan; moan

growl; roar; snarl

hum (of a machine, power lines, etc.); drone (e.g. of an engine); buzz; howl (of the wind)

groan; moan

growl; snarl; roar; howl; bellow

hum (e.g. of a motor); buzz; drone; wiz

device attached to a kite that makes a humming sound when the kite is flown

Physics

beat (acoustic interference)

moan; groan; groaning

moaning; groaning