Definition of "hum"
A hummed tune, i.e. created orally with lips closed.
An often indistinct sound resembling human humming.
Busy activity, like a beehive's buzz.
To make a sound from the vocal chords without pronouncing any real words, with one's lips closed.
To express of affect by humming.
To drone like certain insects naturally do in motion, or sounding similarly.
To buzz, be busily active like a beehive.
To produce low sounds which blend continuously.
To reek, smell bad.
To deceive, or impose on one by some story or device.
Hmm; an inarticulate sound uttered in a pause of speech implying doubt and deliberation.