cataract

noun

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

Did you know?

Cataract dates to the 14th century and comes from the Latin word cataracta, meaning "portcullis." The Latin pertains to the ocular cataract, probably because it obstructs one's vision much like the portcullis's heavy iron grating obstructs passage into a fortress or castle. Cataracta has another meaning, however—"waterfall"—and that meaning gave English 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The summary noted that Trump previously had cataract surgery on both eyes, but did not include a date or dates. Darlene Superville, Chicago Tribune, 13 Apr. 2025 The report also revealed that the president underwent a colonoscopy last July, when he was diagnosed with diverticulitis and a benign polyp, and had cataract surgery at some undetailed point in the past. Matthew Medsger, Boston Herald, 13 Apr. 2025 Some recent surgeries Trump underwent, per the health document, included cataract surgery on both eyes, though dates were not included. Meredith Kile, People.com, 13 Apr. 2025 The report additionally detailed that Trump, at some point, underwent cataract surgery, but did not specify when. Annabella Rosciglione, The Washington Examiner, 13 Apr. 2025 See All Example Sentences for cataract

Word History

Etymology

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

First Known Use

14th century, in the meaning defined at sense 1

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

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Cite this Entry

“Cataract.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cataract. Accessed 22 Apr. 2025.

Kids Definition

cataract

noun
cat·​a·​ract ˈkat-ə-ˌrakt How to pronounce cataract (audio)
1
: a clouding of the lens of the eye or of the transparent cover around it that blocks the passage of light
2
a
: a large waterfall
b
: a sudden rush like a waterfall : flood

Medical Definition

cataract

noun
cat·​a·​ract ˈkat-ə-ˌrakt How to pronounce cataract (audio)
: a clouding of the lens of the eye or its surrounding transparent membrane that obstructs the passage of light

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