1821, from Mod.L. Undina (1657), coined by Paracelsus ("De Nymphis") for a water spirit in his alchemical system, from L. unda "a wave" (see
water). Popularized by Ger. romance "Undine, eine Erzählung" (1811) by Baron F.H.C. La Motte Fouqué. Undinism (1928) was