1. (noun)busyness, hum the state of being or appearing to be actively engaged in an activity "they manifested all the busyness of a pack of beavers"; "there is a constant hum of military preparation"
2. (noun)Harkat-ul-Mujahidin, HUM, Harkat ul-Ansar, HUA, Harkat ul-Mujahedeen, Al Faran, Movement of Holy Warriors an Islamic fundamentalist group in Pakistan that fought the Soviet Union in Afghanistan in the 1980s; now operates as a terrorist organization primarily in Kashmir and seeks Kashmir's accession by Pakistan
3. (verb)hum, humming a humming noise "the hum of distant traffic"
4. (verb)hum sing with closed lips "She hummed a melody"
5. (verb)hum, buzz, seethe be noisy with activity "This office is buzzing with activity"
6. (verb)hum, thrum sound with a monotonous hum
7. (verb)hum make a low continuous sound "The refrigerator is humming"
Definitions of 'HUM'
Webster 1913 Dictionary
1. (noun)HUM a low monotonous noise, as of bees in flight, of a swiftly revolving top, of a wheel, or the like; a drone; a buzz
2. (noun)HUM any inarticulate and buzzing sound
3. (noun)HUM the confused noise of a crowd or of machinery, etc., heard at a distance; as, the hum of industry
4. (noun)HUM a buzz or murmur, as of approbation
5. (noun)HUM an imposition or hoax
6. HUM an inarticulate nasal sound or murmur, like h'm, uttered by a speaker in pause from embarrassment, affectation, etc
7. HUM a kind of strong drink formerly used
8. HUM ahem; hem; an inarticulate sound uttered in a pause of speech implying doubt and deliberation
9. (verb)HUM to make a low, prolonged sound, like that of a bee in flight; to drone; to murmur; to buzz; as, a top hums
10. (verb)HUM to make a nasal sound, like that of the letter m prolonged, without opening the mouth, or articulating; to mumble in monotonous undertone; to drone
11. (verb)HUM to make an inarticulate sound, like h'm, through the nose in the process of speaking, from embarrassment or a affectation; to hem
12. (verb)HUM to express satisfaction by a humming noise
13. (verb)HUM to have the sensation of a humming noise; as, my head hums, -- a pathological condition
14. (verb)HUM to sing with shut mouth; to murmur without articulation; to mumble; as, to hum a tune
15. (verb)HUM to express satisfaction with by humming
16. (verb)HUM to flatter by approving; to cajole; to impose on; to humbug
Definition of HUM 
