cataclysm

UK: /ˈkætəklɪzəm/ US: /ˈkætəˌklɪzəm/ ,(kat′ə kliz′əm)

WordReference Random House Learner's Dictionary of American English © 2025

cat•a•clysm /ˈkætəˌklɪzəm/   n. [countable]

1. a violent and sudden event that produces great social changes;
   upheaval:
   The revolution was a cataclysm of major importance in that century.
2. Geography a sudden and violent action producing changes in the earth's surface, as a flood or earthquake;
   catastrophe.

cat•a•clys•mic, cat•a•clys•mal, adj. 
cat•a•clys•mi•cal•ly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2025

cat•a•clysm  (kat′ə kliz′əm), n. 

1. any violent upheaval, esp. one of a social or political nature.
2. Geography [Physical Geog.] a sudden and violent physical action producing changes in the earth's surface.
3. an extensive flood;
   deluge.

• Greek kataklysmós flood (akin to kataklýzein to flood), equivalent. to kata- cata- + klysmós a washing
• Late Latin cataclysmos (Vulgate)
• 1625–35

Synonyms

• 1. See disaster. 

Collins Concise English Dictionary © HarperCollins Publishers::

cataclysm / ˈkætəˌklɪzəm/ noun

1. a violent upheaval, esp of a political, military, or social nature
2. a disastrous flood; deluge

Etymology: 17th Century: via French from Latin, from Greek kataklusmos deluge, from katakluzein to flood, from kluzein to wash

ˌcataˈclysmic, ˌcataˈclysmal adjective

ˌcataˈclysmically adverb