siphon n.

late 14c., "water hose; tube for drawing fluid from a swelling," from Latin sipho (genitive siphonis) "a siphon," from Greek siphōn "pipe, tube for drawing wine from a cask," a technical term of unknown origin and uncertain etymology. The meaning "glass or metal tube bent so that one leg is longer, used to drain off liquid by atmospheric pressure" is from 1650s. Related: Siphonal; siphonic. In zoology, a small one is a siphuncle, and a creature that has them is siphuncled.

1859, "convey (a liquid) by means of a siphon," from siphon (n.). The figurative sense of "draw off, divert" is recorded by 1940. Related: Siphoned; siphoning; siphonage.