/ ˈkætərækt; NAmE / noun
1.
a medical condition that affects the lens of the eye and causes a gradual loss of sight
2.
( literary ) a large steep waterfall
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WORD ORIGIN
late Middle English : from Latin cataracta waterfall, floodgate, also portcullis (medical sense 1 probably being a figurative use of this), from Greek kataraktēs down-rushing, from katarassein , from kata- down + arassein strike, smash.