cat·​a·​ract | \ ˈka-tə-ˌrakt How to pronounce cataract (audio) \

Definition of cataract

1 [Middle English, from Middle French or Medieval Latin; Middle French catharacte, from Medieval Latin cataracta, from Latin, portcullis] : a clouding of the lens of the eye or of its surrounding transparent membrane that obstructs the passage of light
2a obsolete : waterspout
b : waterfall especially : a large one over a precipice
c : steep rapids in a river the cataracts of the Nile
d : downpour, flood cataracts of rain cataracts of information

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Other Words from cataract

cataractous \ ˌka-​tə-​ˈrak-​təs How to pronounce cataract (audio) \ adjective

Synonyms for cataract


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The meaning of "cataract" we're most familiar with is also the oldest. It dates to the 14th century and comes from the Latin word cataracta, meaning "portcullis," probably because the ocular cataract obstructs vision in a way reminiscent of the way the portcullis's heavy iron grating obstructs passage into a fortress or castle. Latin cataracta has another meaning, however-"waterfall"-and that meaning gave us the water-related meanings that came in later centuries. The connection between the two Latin meanings can be seen in katarassein, the Greek source of cataracta. It means "to dash down"-an action we see in both the slamming portcullis and the cascading waterfall.

Examples of cataract in a Sentence

the roaring cataract is one of the park's most majestic sights in spring the melting snows usually produce a cataract that inundates the valley
Recent Examples on the Web At 57 feet high, Blackwater Falls is the state’s highest cataract, and the centerpiece of West Virginia’s most visited state park. Susan Glaser, cleveland, 6 May 2021 Others who have already benefited from Ruit's cataract surgery likened him to a god. Binaj Gurubacharya, Star Tribune, 30 Apr. 2021 That explosion also caused a cataract, excessive tissue damage and extensive damage to his left retina. Kristin Wilson And Paul Leblanc, CNN, 29 Apr. 2021 Plus, research suggests that greater vitamin A and beta carotene intake intake may be inversely associated with risk for cataract. Good Housekeeping, 30 Sep. 2020 Priestdaddy begins with events that unfolded after Kendall was diagnosed with a rare type of cataract; the couple managed to raise funds for eye surgery online but still ran out of money and moved in with her parents in Kansas City in 2013. Joanne Mcneil, Vulture, 12 Feb. 2021 There are more than 2 million cataract surgeries performed in the United States each year. Jennifer Vishnevsky, Redbook, 9 June 2020 Late that month, Nelson Martinez said officials came and tested every man in Central 2, the dorm the 48-year-old with diabetes and asthma was living, still recovering from cataract surgery. Lisa Riordan Seville, NBC News, 19 Dec. 2020 Aravind is able to make eye care affordable in part because the team started its own manufacturing facility to produce intraocular lenses, which are implanted as part of cataract treatments. Science, 3 Dec. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'cataract.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of cataract

14th century, in the meaning defined at sense 1

History and Etymology for cataract

Latin cataracta waterfall, portcullis, from Greek kataraktēs, from katarassein to dash down, from kata- + arassein to strike, dash

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Time Traveler for cataract

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The first known use of cataract was in the 14th century

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Last Updated

10 May 2021

Cite this Entry

“Cataract.” Dictionary, Merriam-Webster, Accessed 25 Jun. 2021.

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More Definitions for cataract



English Language Learners Definition of cataract

medical : a condition in which a part of your eye (called the lens) becomes cloudy and you cannot see well
literary : a large waterfall


cat·​a·​ract | \ ˈka-tə-ˌrakt How to pronounce cataract (audio) \

Kids Definition of cataract

1 : a clouding of the lens of the eye or of the cover around the lens that blocks the passage of light
2 : a large waterfall
3 : a sudden rush or flow like a waterfall


cat·​a·​ract | \ ˈkat-ə-ˌrakt How to pronounce cataract (audio) \

Medical Definition of cataract

: a clouding of the lens of the eye or its surrounding transparent membrane that obstructs the passage of light

More from Merriam-Webster on cataract

Nglish: Translation of cataract for Spanish Speakers

Britannica English: Translation of cataract for Arabic Speakers Encyclopedia article about cataract


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