Source : Webster's Revised Unabridged Dictionary (1913)

Explosion \Ex*plo"sion\, n. [L. explosio a driving off by
   clapping: cf. F. explosion explosion. See {Explode}.]
   1. The act of exploding; detonation; a chemical action which
      causes the sudden formation of a great volume of expanded
      gas; as, the explosion of gunpowder, of fire damp,etc.

   2. A bursting with violence and loud noise, because of
      internal pressure; as, the explosion of a gun, a bomb, a
      steam boiler, etc.

   3. A violent outburst of feeling, manifested by excited
      language, action, etc.; as, an explosion of wrath.

            A formidable explosion of high-church fanaticism.
                                                  --Macaulay.

Source : WordNet®

explosion
     n 1: a violent release of energy caused by a chemical or nuclear
          reaction [syn: {detonation}, {blowup}]
     2: the act of exploding or bursting something; "the explosion
        of the firecrackers awoke the children"; "the burst of an
        atom bomb creates enormous radiation aloft" [syn: {burst}]
     3: a sudden great increase; "the population explosion"; "the
        information explosion"
     4: the noise caused by an explosion; "the explosion was heard a
        mile away"
     5: the terminal forced release of pressure built up during the
        occlusive phase of a stop consonant [syn: {plosion}]
     6: a sudden outburst; "an explosion of laughter"; "an explosion
        of rage"
     7: a golf shot from a bunker that typically moves sand as well
        as the golf ball