collapse

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

• intransitive verb To fall down or inward suddenly; cave in.
• intransitive verb To break down suddenly in strength or health and thereby cease to function.
• intransitive verb To fold compactly.
• intransitive verb To cause to fold, break down, or fall down or inward.
• noun The act of falling down or inward, as from loss of supports.
• noun An abrupt failure of function, strength, or health; a breakdown.
• noun An abrupt loss of perceived value or of effect.

from The Century Dictionary.

• noun A falling in or together, as of the sides of a hollow vessel.
• noun Figuratively, a sudden and complete failure of any kind; a breakdown.
• noun In medicine, an extreme sinking or depression; a more or less sudden failure of the vital powers: as, the stage of collapse in cholera.
• To fall together, or into an irregular mass or flattened form, through loss of firm connection or rigidity and support of the parts or loss of the contents, as a building through the falling in of its sides, or an inflated bladder from escape of the air contained in it.
• Figuratively— To break down; go to pieces; come to nothing; fail; become ruined: as, the project collapsed.
• In pathology, to sink into extreme weakness or physical depression in the course of a disease.
• To appear as if collapsing; lose strength, courage, etc.; subside; cease to assert one's self or push one's self forward: as, after that rebuke he collapsed.

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

• intransitive verb To fall together suddenly, as the sides of a hollow vessel; to close by falling or shrinking together; to have the sides or parts of (a thing) fall in together, or be crushed in together.
• intransitive verb To fail suddenly and completely, like something hollow when subject to too much pressure; to undergo a collapse.
• noun A falling together suddenly, as of the sides of a hollow vessel.
• noun colloq. A sudden and complete failure; an utter failure of any kind; a breakdown.
• noun (Med.) Extreme depression or sudden failing of all the vital powers, as the result of disease, injury, or nervous disturbance.

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

• verb intransitive To fall down suddenly; to cave in
• verb intransitive To cease to function due to a sudden breakdown
• verb intransitive To fold compactly
• verb cricket For several batsmen to get out in quick succession
• verb transitive To cause something to collapse.
• verb intransitive To pass out and fall to the floor or ground, as from exhaustion or other illness; to faint
• noun The act of collapsing
• noun Constant function, one-valued function (in automata theory) (in particular application causing a reset)

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

• verb collapse due to fatigue, an illness, or a sudden attack
• verb fall apart
• verb break down, literally or metaphorically
• verb suffer a nervous breakdown
• noun a sudden large decline of business or the prices of stocks (especially one that causes additional failures)
• verb cause to burst
• noun an abrupt failure of function or complete physical exhaustion
• verb fold or close up
• noun a natural event caused by something suddenly falling down or caving in
• verb lose significance, effectiveness, or value
• noun the act of throwing yourself down