Definition of cataract
1 [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
cataractousplay \ˌka-tə-ˈrak-təs\ adjective
cataract was our Word of the Day on 05/08/2014. Hear the podcast!
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
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.
Origin and Etymology of cataract
Latin cataracta waterfall, portcullis, from Greek kataraktēs, from katarassein to dash down, from kata- + arassein to strike, dash
First Known Use: 14th century
CATARACT Defined for English Language Learners
Definition of cataract for English Language Learners
medical : a condition in which a part of your eye (called the lens) becomes cloudy and you cannot see well
: a large waterfall
CATARACT Defined for Kids
Definition of cataract for Students
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
Medical Definition of cataract
: a clouding of the lens of the eye or its surrounding transparent membrane that obstructs the passage of light
Learn More about cataract
Seen and Heard
What made you want to look up cataract? Please tell us where you read or heard it (including the quote, if possible).