Nubian kadis, Berber kadiska, both meaning "cat"). Arabic qitt "tomcat" may be from the same source. Cats were domestic in Egypt from c.2000 B.C.E., but not a familiar household animal to classical Greeks and Romans. The nine lives have been proverbial since at least 1560s. Extended to lions, tigers, etc. c.1600. As a term of contempt for a woman, from early 13c. Slang sense of "prostitute" is from at least c.1400. Slang sense of "fellow, guy," is from 1920, originally in U.S. Black Eng.; narrower sense of "jazz enthusiast" is recorded from 1931. Catnap is from 1823; catfish is from c.1620. Cat's-cradle is from 1768. Cat-o'-nine-tails (1690s), probably so called in reference to its "claws," was legal instrument of punishment in British Navy until 1881. Cat's paw (1769, but cat's foot in the same sense, 1597) refers to old folk tale in which the monkey tricks the cat into pawing chestnuts from a fire; the monkey gets the nuts, the cat gets a burnt paw. To rain cats and dogs (c.1652) is probably an extension of cats and dogs as proverbial for "strife, enmity" (1570s). Cat-witted "small-minded, obstinate, and spiteful" (1670s) deserved to survive. For Cat's meow, cat's pajamas, see bee's knees
1975, medical acronym for computerized axial tomography or something like it.