Yes, boom is a Scrabble word!

Verb

1. Make a resonant sound, like artillery

2. Hit hard

3. Be the case that thunder is being heard

4. Make a deep hollow sound

5. Grow vigorously

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)

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