Noun
1. a deep prolonged loud noise
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 lik an assembly line"4. a pole carrying an overhead microphone projected over a film or tv set
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