Cat"a*clysm (?), n. [L.
cataclysmos, Gr. kataklysmo`s, from ? to dash
over, inundate; kata` downward, against + ? to wash
or dash 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.