Cat"a*clysm (?), n. [L. cataclysmos, Gr. , from to dash over, inundate; downward, against + to wash or dash or over: cf. F. cataclysme.]
1.
An extensive overflow or sweeping flood of water; a deluge.
2. Geol.
Any violent catastrophe, involving sudden and extensive changes of the earth's surface.
© Webster 1913.