WordWeb Online

1. A deep prolonged loud noise
   - roar, roaring, thunder
    
2. A state of economic prosperity
    
3. A sudden happening that brings good fortune (as a sudden opportunity to make money)
   "the demand for testing has created a boom for those unregulated laboratories where boxes of specimen jars are processed like an assembly line";
   - bonanza, gold rush, gravy [informal], godsend, manna from heaven, windfall, bunce [Brit, informal]
    
4. A pole carrying an overhead microphone projected over a film or tv set
   - microphone boom
    
5. Any of various more-or-less horizontal spars or poles used to extend the foot of a sail or for handling cargo or in mooring
    
6. A floating barrier used to obstruct the entry of a harbour, contain oil spills, etc.

1. Make a resonant sound, like artillery
   "His deep voice boomed through the hall";
   - din
    
2. Hit with great force
   "He boomed a 3-run homer";
   - smash, nail, blast
    
3. Be the case that thunder is being heard
   "Whenever it booms, my dog crawls under the bed";
   - thunder
    
4. Make a deep hollow sound
   "Her voice booms out the words of the song";
   - boom out
    
5. Grow vigorously
   "business is booming";
   - thrive, flourish, expand

Derived forms: booms, booming, boomed

Type of: go, grow, happening, hit, natural event, noise, occurrence, occurrent, pole, prosperity, sound, spar

Part of: sailing ship, sailing vessel

Encyclopedia: Boom, Like That