Booming means deep, loud and echoing. A booming voice, booming guns, booming across the valley.
The depth is what makes it booming rather than merely loud — low frequencies carry further and round corners better, which is why a booming voice fills a hall. The other sense is economic: a booming market is growing fast. Note boom, which is imitative of the sound and older than the economic use.
1adjectiveboomingDeep, loud and echoing.
“The headmaster's booming voice echoed down the corridor.”
2adjectivegrowingGrowing fast, of a market.
“The town's tourist trade is booming, with new hotels opening every year.”
booming is a quality of sound or growth.
Practised in Sounds & Noises