Origin and history of anode

"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.

late Old English, the second book of the Old Testament, from Latin exodus, from Greek exodos "a military expedition; a solemn procession; departure; death," literally "a going out," from ex "out" (see ex-) + hodos "a way, path, road; a ride, journey, march," figuratively "way out, means," a word of uncertain origin.

The book is so called because it tells of the departure of the Israelites from Egypt under the leadership of Moses. General sense (with lower-case -e-) "departure from a place," especially "the migration of large bodies of people or animals from one country or region to another," is from 1620s.

Beekes derives the Greek word from PIE *sod- "course" and says it is traditionally connected with Slavic words for "course" (such as Russian xod "course, progress," "which might have been borrowed from Iranian") and adds that it is perhaps also related to Sanskrit a-sad- "to tread on, go on," Avestan apa-had- "to go away; become weak," "but the relation between them is unclear, as is the connection to the PIE root *sed- "sit" (proposed in Watkins, etc.)."