Cataract
Definition: a waterfall; a disorder of the eye
This is from the Greek “kataraktes,” which means “downrush.”
Clearly, most people know “cataract” from the disorder of the mammalian eye. So, how did that get named for a waterfall? Wikipedia has some theories:
As rapidly running water turns white, so the term may have been used metaphorically to describe the similar appearance of mature ocular opacities. In Latin, cataracta had the alternative meaning “portcullis” and the name possibly passed through French to form the English meaning “eye disease” (early 15th century), on the notion of “obstruction”. Early Persian physicians called the term nazul-i-ah, or “descent of the water” – vulgarised into waterfall disease or cataract – believing such blindness to be caused by an outpouring of corrupt humour into the eye.
The most famous cataracts are those on the Nile. They have a Wikipedia page all their own, which says:
The Cataracts of the Nile are shallow lengths (or whitewater rapids) of the Nile river, between Khartoum and Aswan, where the surface of the water is broken by many small boulders and stones jutting out of the river bed, as well as many rocky islets. In some places, these stretches are punctuated by whitewater, while at others the water flow is smoother but still shallow.
Why I Looked It Up
I had known of the eye condition.
However, in Sioux Falls, a famous historical building was The Cataract Hotel. This building was considered the center of the city, to the point where the street directions are based on it. Anything north of 9th and Phillips (where the Cataract Hotel once stood) is “north,” anything south of that intersection is south, etc.
The Cataract Hotel burned down multiple times, the last fire in the early 70s. In the mid-70s, the current Wells Fargo Tower was built on the location.
I always thought the name was a little odd, but I never put together the traditional definition of “cataract” with the fact that Sioux Falls is named for a waterfall (that’s generous; the Sioux Falls’ namesake are really a set of terraced rapids, though after a significant rainfall, they can be quite powerful – although, see below for the same namesake on the mighty Nile).
Then, while watching the recent remake of the Agatha Christie novel Death on the Nile, I noted that part of the plot is set at the Old Cataract Hotel in Aswan, Egypt (in the 1930s). The name of the hotel was printed on the screen, which peaked my interest given the similarity to the name of the Sioux Falls hotel.
In the case of the Egyptian hotel, it was so-named because it sat on the banks of the Nile at the Cataracts of the Nile, which are a series of whitewater rapids, on an otherwise placid river.
Postscript
Added on
In Kingmakers, I found this is a description of a British rescue mission into Sudan:
Delayed by the Nile’s treacherous sixth cataract…
Here is the sixth cataract on Google Maps. You can see how the river narrows considerably.