implosion

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A violent collapse inward, as of a highly evacuated glass vessel.
• noun Violent compression.
• noun The inward collapse of a building that is being demolished in a controlled fashion by the weakening and breaking of structural members by explosives.
• noun A catastrophic failure.
• noun Linguistics The pronunciation of a stop consonant with the breath drawn in.

from The Century Dictionary.

• noun A sudden collapse or bursting inward: opposed to explosion.
• noun In phonology, see the extract.

from the GNU version of the Collaborative International Dictionary of English.

• noun A bursting inwards, as of a vessel from which the air has been exhausted; -- contrasted with explosion.
• noun The inward-moving detonation wave cause by detonation of explosives arrayed spherically around a core; -- a technique used in atomic bombs to compress fissionable material to allow a chain reaction time to produce an explosion of the fissionable material.
• noun (Phon.) A sudden compression of the air in the mouth, simultaneously with and affecting the sound made by the closure of the organs in uttering p, t, or k, at the end of a syllable (see Guide to Pronunciation, §§159, 189); also, a similar compression made by an upward thrust of the larynx without any accompanying explosive action, as in the peculiar sound of b, d, and g, heard in Southern Germany.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The inrush of air in forming a suction stop.
• noun The action of imploding.
• noun The act or action of bringing to or as if to a center.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a sudden inward collapse
• noun the initial occluded phase of a stop consonant