For most people, the word greyhound probably triggers the idea of a skinny gray dog, while the word nightmare conjures up the image of a horse galloping through the night.
Here are five words whose names suggest meanings that aren’t there.
catgut: The dried and twisted intestines of sheep, also of the horse and ass; used for the strings of musical instruments; also as bands in lathes, clocks, etc.
The word in English probably originated as “kitgut,” from kit, “small fiddle used by dancing teachers.” This “kit” probably derives from OE cythere, from Latin cithara, from Greek kithara. The OED notes that the Dutch word kattedarm does mean “guts or intestines of the cat,” but adds that there’s no evidence that catgut was ever used for the purpose of stringing a musical instrument.
greyhound: A variety of dog used in the chase, characterized by its long slender body, and long legs, by the keenness of its sight, and by its great speed in running.
Old English had the word grighund. Hund, of course, meant “dog.” The “grig” part comes from an Old Norse word for “bitch.”
nightmare: Now usually: a bad dream producing feelings of distress. Originally (usu. with the): a feeling of suffocation or great distress experienced during sleep.
A “nightmare” was a female spirit or monster supposed to settle on and produce a feeling of suffocation in a sleeping person or animal. This kind of “mare” has cognates in several languages. It’s the “mar” in French cauchemar (nightmare), and is related to Irish morrigain, “queen of the elves.” It is not related to the mare that means “female horse.”
mustard gas: A colorless oily liquid whose vapor is a powerful irritant and vesicant acting directly on the skin, used in chemical warfare, originally at Ypres during the First World War (1914-18).
Mustard gas isn’t made from mustard, and it’s not a gas. It was yellow and those unfortunate enough to get a whiff of it thought it resembled the smell of mustard, garlic, or horseradish. It’s an atomized liquid.
heartburn: An uneasy burning sensation in the lower part of the chest, due to putrefactive fermentation of the food in the stomach
Greek kardia could mean both “heart” and “stomach.” Greek kardiakos meant “pertaining to the heart. Latin cardiacus could mean “pertaining to the stomach.” The term “heartburn” arose from confusion between the areas of heart and stomach.