Who would believe that the furry, leaf-munching caterpillar has feline origins? But it does. Its name derives from the Old French chatte pelouse (hairy cat), a rather fanciful stretch of the imagination. But that's not all. The English word "piller" (robber), was eventually added to the word to denote the creature's garden-plundering habits. According to pundit Harry Shaw, Bishop Hugh Latimer centuries ago referred to "extortioners, caterpillars, and usurers" all in the same breath. In modern French, however, the word for caterpillar is chenille, from the Latin for "little dog."
Kitty-corner was once a cat
This term has nothing to do with cats crossing intersections. Sometimes written "cater-corner" or "catty-corner," its origin is from the French word quatre (four), as in four corners. "Cater" is the best that English speakers could manage with that one, claims word buff Michael Macrone. Eventually, he adds, people settled on the more-familiar "catty" and, later, "kitty."
Cloudy origins for 'raining cats and dogs'
Almost every word etymology discusses this familiar phrase, probably because it has so many possible origins, all of them colorful. Three theories predominate: Greek scholars suggest that the original meaning of the phrase has nothing to do with pets. They explain the phrase as a mispronunciation of the Greek word for waterfall - catadupa (rushing water).
Another theory links cloudbursts to Norse weather myths. In ancient times, cats were associated with frisky rainstorms and dogs with wind, making for a gusty downpour. The most recent theory dates to 17th-century England, where cats and dogs often ran wild. After a lashing rain, many were found drowned in the gutterless streets.
As improbable as it sounds, people may have imagined that "it had rained cats and dogs," suggests linguist Rudolf Brasch.
Letting the cat out of the bag
This phrase, meaning to disclose a secret, has rural origins. Country folks used to try to trick the unwary by placing a cat, rather than a suckling pig, in a bag that was then offered for sale at market. A naive person would purchase "a pig in a poke" without opening the sack to examine the contents. A wise buyer would look before purchasing, and let the cat out of the bag.