n.

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);
   bonanza, gold rush, gravy, godsend, manna from heaven, windfall, bunce
   
   • the demand for testing has created a boom for those unregulated laboratories where boxes of specimen jars are processed like an assembly line
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

v.

1. make a resonant sound, like artillery;
   din
   
   • His deep voice boomed through the hall
2. hit hard;
   smash, nail, blast
   
   • He smashed a 3-run homer
3. be the case that thunder is being heard;
   thunder
   
   • Whenever it thunders, my dog crawls under the bed
4. make a deep hollow sound;
   boom out
   
   • Her voice booms out the words of the song
5. grow stronger;
   prosper, thrive, get ahead, flourish, expand
   
   • The economy was booming