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 cataractous (audio) \ adjective

Synonyms for cataract


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Did You Know?

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 The newborn had a rare condition — a congenital cataract — in his right eye. Jason Frakes, The Courier-Journal, "Meet Finnick the Fierce, the one-eyed Kentucky Derby horse who once beat Tiz the Law," 2 Sep. 2020 According to my mom’s ophthalmologist, her cataract was very dense. Jennifer Vishnevsky, Redbook, "My Mom Put Off Cataract Surgery: Here’s What You Need to Know," 9 June 2020 But when Gilster’s mare Southern Classic dropped her second foal in April of 2017, the newborn had a congenital cataract in its right eye. Jason Frakes, The Courier-Journal, "These Kentucky Derby horse names have ties to Cardi B, Roger Federer, Notre Dame and more," 2 Sep. 2020 Uveitis is a leading cause of complications after cataract surgery in dogs, Scott says, and the management of postoperative inflammation inside the eye is a major challenge in both veterinary and human ophthalmology. Texas A&m University, Houston Chronicle, "PET TALK: Turmeric and canine uveitis: Not so far-fetched," 29 Aug. 2020 Six months after cataract surgery, images started to pixelate in the center of my left eye. Liane Kupferberg Carter, Longreads, "Sight and Insight," 10 Aug. 2020 Savannah recently had cataract surgery on her right eye. Kayla Keegan, Good Housekeeping, "Here's the Latest on 'Today' Star Savannah Guthrie Following Her Cataract Eye Surgery," 21 July 2020 Putting off cataract surgery isn’t always a bad idea. Jennifer Vishnevsky, Redbook, "My Mom Put Off Cataract Surgery: Here’s What You Need to Know," 9 June 2020 The exhibition will feature inventors from Kevlar inventor Stephanie Kwolek, and Folia Water filter creator Theresa Dankovich, to Patricia Bath, who made a cataract removal device in 1981 called the Laserphaco Probe. Roger Catlin, Smithsonian Magazine, "Twenty Smithsonian Shows to See in 2020," 6 Feb. 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

30 Sep 2020

Cite this Entry

“Cataract.” Dictionary, Merriam-Webster, Accessed 30 Oct. 2020.

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More Definitions for cataract


How to pronounce cataract (audio)

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

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