Decrease and Collapse

decrease

A change downward.
- usage: "there was a decrease in his temperature as the fever subsided"; "there was a sharp drop-off in sales"
- synonyms: lessening, drop-off
A process of becoming smaller or shorter.
- synonyms: decrement
The amount by which something decreases.
- synonyms: decrement
The act of decreasing or reducing something.
- synonyms: diminution, reduction, step-down

Decrease in size, extent, or range.
- usage: "The amount of homework decreased towards the end of the semester"; "The cabin pressure fell dramatically"; "her weight fell to under a hundred pounds"; "his voice fell to a whisper"
- synonyms: diminish, lessen, fall
Make smaller.
- usage: "He decreased his staff"
- synonyms: lessen, minify

(v.t.) To cause to grow less; to diminish gradually; as, extravagance decreases one's means.
(v.) A becoming less; gradual diminution; decay; as, a decrease of revenue or of strength.
(n.) To grow less, -- opposed to increase; to be diminished gradually, in size, degree, number, duration, etc. or in strength, quality or excellence; as, they days decrease in length from June to December.
(v.) The wane of the moon.

Webster's Revised Unabridged Dictionary

collapse

An abrupt failure of function or complete physical exhaustion.
- usage: "the commander's prostration demoralized his men"
- synonyms: prostration
A natural event caused by something suddenly falling down or caving in.
- usage: "the roof is in danger of collapse"; "the collapse of the old star under its own gravity"
The act of throwing yourself down.
- usage: "he landed on the bed with a great flop"
- synonyms: flop
A sudden large decline of business or the prices of stocks (especially one that causes additional failures.
- synonyms: crash

Break down, literally or metaphorically.
- usage: "The wall collapsed"; "The business collapsed"; "The dam broke"; "The roof collapsed"; "The wall gave in"; "The roof finally gave under the weight of the ice"
- synonyms: fall in, cave in, give, give way, break, founder
Collapse due to fatigue, an illness, or a sudden attack.
- synonyms: break down
Fold or close up.
- usage: "fold up your umbrella"; "collapse the music stand"
Fall apart.
- usage: "the building crumbled after the explosion"; "Negotiations broke down"
- synonyms: crumble, crumple, tumble, break down
Cause to burst.
- usage: "The ice broke the pipe"
- synonyms: burst
Suffer a nervous breakdown.
- synonyms: crack up, crack, crock up, break up
Lose significance, effectiveness, or value.
- usage: "The school system is collapsing"; "The stock market collapsed"

(v.i.) 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; as, a flue in the boiler of a steam engine sometimes collapses.
(n.) A sudden and complete failure; an utter failure of any kind; a breakdown.
(n.) A falling together suddenly, as of the sides of a hollow vessel.
(v.i.) To fail suddenly and completely, like something hollow when subject to too much pressure; to undergo a collapse; as, Maximilian's government collapsed soon after the French army left Mexico; many financial projects collapse after attaining some success and importance.
(n.) Extreme depression or sudden failing of all the vital powers, as the result of disease, injury or nervous disturbance.

Webster's Revised Unabridged Dictionary