WordWeb Online

1. A humming noise
   "the humming of distant traffic"
   - hum
    
2. The act of singing with closed lips

1. Sing with closed lips
   "She hummed a melody"
    
2. Be noisy with activity
   "This office is humming with activity"
   - buzz, seethe
    
3. Sound with a monotonous hum
   - thrum
    
4. Make a low continuous sound
   "The refrigerator is humming"

Derived forms: hummings

See also: hummer

Type of: be, go, make noise, noise, resound, sing, singing, sound, vocalising [Brit], vocalizing

Encyclopedia: Hum Hum, Croatia