This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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n. A violent upheaval that causes great destruction or brings about a fundamental change.

n. A violent and sudden change in the earth's crust.

n. A devastating flood.

n. A sudden, violent event.

n. A sudden and violent change in the earth's crust.

n. A great flood.

n. An extensive overflow or sweeping flood of water; a deluge.

n. Any violent catastrophe, involving sudden and extensive changes of the earth's surface.

n. A deluge or an overflowing of water; a flood; specifically, the Noachian flood.

n. In geology, an inundation or deluge, or other violent and sudden physical action of great extent, supposed to have been the efficient cause of various phenomena (as of the deposition of different formations of diluvium or drift) for which the gradual action of moderate currents, or that of ice, is considered to have been inadequate.

n. Figuratively, a sudden or violent action of overwhelming force and extended sweep.

n. a sudden violent change in the earth's surface

n. an event resulting in great loss and misfortune

"Some people swore the year 2000 would bring technological chaos, or an old-fashioned End of the Word cataclysm."

theory of cataclysms    of catastrophes   

catastrophe   

cataclysmic   

deluge    catastrophe    upheaval   

upheaval    catastrophe    conflagration    eruption    convulsion    turmoil    holocaust    earthquake    thunderstorm    perturbations