Pronunciation: (ik-splō'zhun), [key]
1. an act or instance of exploding; a violent expansion or bursting with noise, as of gunpowder or a boiler (opposed to implosion).
2. the noise itself: The loud explosion woke them.
3. a violent outburst, as of laughter or anger.
4. a sudden, rapid, or great increase: a population explosion.
5. the burning of the mixture of fuel and air in an internal-combustion engine.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.