undine (n.) Look up undine at Dictionary.com
1821, from Modern Latin Undina (1650s), coined by Paracelsus ("De Nymphis") for a water spirit in his alchemical system, from Latin unda "a wave" (see water). Popularized by German romance "Undine, eine Erzählung" (1811) by Baron F.H.C. La Motte Fouqué. Undinism (1928) was coined by sex researcher Havelock Ellis to describe the fetish for urine (which Ellis had); nowadays it would be called urophilia.