"negative pole of an electric current," 1834, from Latinized form of Greek kathodos "a going down, a way down," from kata "down" (see cata-) + hodos "a way, path, track, road," a word of uncertain origin (see Exodus). Proposed by the Rev. William Whewell, English polymath, and published by English chemist and physicist Michael Faraday. So called from the path the electric current was supposed to take. Related: Cathodic; cathodal. Cathode ray is attested by 1880, but the phenomenon was known from 1859; cathode ray tube is from 1905.
updated on November 14, 2022