cataract

noun cat·a·ract \ ˈka-tə-ˌrakt \

|Updated on: 2 Aug 2018

Definition of cataract

[Middle English, from Medieval French or Medieval Latin; Medieval 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

2 a 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

—

cataractous

play \ˌka-tə-ˈrak-təs\ adjective

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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 of cataract from the Web

Alcon also manufactures medical devices, particularly those used in eye surgeries such as procedures for treatment of cataracts, as well as laser eye surgery.

— gordon dickson, star-telegram, "No need to shed tears yet. Alcon promises to stay in Fort Worth after spinoff," 9 July 2018
Exposure can cause an array of health problems, including cancers, cataracts and digestive ailments.

— New York Times, "Decades Later and Far Away, Chernobyl Disaster Still Contaminates Milk," 8 June 2018
When the ozone layer is weakened, more UV rays can get through and affect humans, making them prone to skin cancer, cataracts and other diseases.

— james griffiths, CNN, "Ozone-destroying emissions are on the rise and scientists don't know why," 16 May 2018
The zeaxanthin is protective against cataracts and macular degeneration.

— sheah rarback, miamiherald, "Ubiquitous mangos taste good - and are good for you, too," 29 June 2018
Photographer: Manaure Quintero/Bloomberg A cataract of confetti almost obscures Maduro at a rally in Caracas.

— philip brian tabuas, Bloomberg.com, "Venezuela Votes in a Presidential Election. Enthusiasm Is Absent," 19 May 2018
When that stops working, the only way to cure cataracts is surgery, the Mayo Clinic says.

— korin miller, SELF, "6 Weird Reasons Your Vision Is Blurry," 4 May 2018
Ultraviolet rays may play a role in the development of cataracts as well as growths on the surface of the eye called pterygiums, which can impede your vision.

— amanda gardner, Health.com, "Why Those Tiny Sunglasses Celebs Love Aren't Actually Good for Your Eyes," 13 June 2018
In the years after the attack, some survivors would endure amputation, paralysis, severe scarring, twisted torsos and limbs, cataracts, thyroid disease, and heart disease.

— Daily Intelligencer, "This Is What a Nuclear Bomb Looks Like," 12 June 2018

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.

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.