Boom

a deep prolonged loud noise

a state of economic prosperity

a sudden happening that brings good fortune (as a sudden opportunity to make money)

a pole carrying an overhead microphone projected over a film or tv set

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

make a resonant sound, like artillery

hit hard

be the case that thunder is being heard

make a deep hollow sound

grow vigorously