cataract

Etymology

From Middle English cataract, cateract, cataracta, from Latin cataracta (“waterfall, portcullis”), from Ancient Greek καταρράκτης (katarrháktēs), from καταράσσω (katarássō, “I pour down”), from κατα- (kata-, “down”) + ἀράσσω (arássō, “to strike, dash”). Its pathological sense probably came from its alternative sense in Latin, “portcullis”, through French through the notion of “obstruction”, in this case, of vision.

noun

1. (obsolete) A waterspout.
2. A large waterfall; steep rapids in a river.
   The cataracts on the Nile helped to compartment Upper Egypt.
3. A flood of water.
4. (figurative) An overwhelming downpour or rush.
   His cataract of eloquence
   As if on cue came a cataract of explosions. She turned on her heel and scurried back to the courtyard and down into the school’s basement. The dirt floor, low ceiling and unfinished stone walls were barely illuminated by candles and a dim string of green decorative lights. 2022-05-19, James Verini, “Surviving the Siege of Kharkiv”, in The New York Times Magazine
5. (pathology) A clouding of the lens in the eye leading to a decrease in vision.
   Rarely, a dense, swollen neglected cataract precipitates an angle-closure glaucoma. 1999, J. J. Gallo, J. Busby-Whitehead, W. Reichel, P. V. Rabins, R. A. Silliman, Reichel’s Care of the Elderly, page 563