Ondine comes from Latin unda, "wave," through French, and refers to a water spirit in legend.
Ondine descends from the Latin *unda*, meaning "wave," and entered the European imagination through Paracelsus, the sixteenth-century Swiss alchemist and physician who systematized the four elemental spirits in his treatise *Liber de Nymphis*. He designated undines as the water elementals — beings who inhabited rivers, lakes, and seas, possessing beauty and grace but lacking an immortal soul unless they married a mortal man. This mythology gave rise to Friedrich de la Motte Fouqué's 1811 novella *Undine*, a melancholy romance in which the water spirit gains a soul through love but is ultimately destroyed by human inconstancy.
The French spelling Ondine became the title of Jean Giraudoux's celebrated 1939 play, in which a water nymph falls in love with a knight named Hans and experiences the full tragedy of loving a creature bound to mortality and faithlessness. The play was revived famously in the 1950s with Audrey Hepburn in the role on Broadway, bringing the name — and its shimmering, aquatic mythology — before a new generation. Ondine also entered medical lexicon as "Ondine's curse," a rare condition affecting autonomic breathing, drawn from a dark variant of the legend in which the water spirit curses her unfaithful husband to remember to breathe.
As a given name, Ondine is extraordinarily rare, which is precisely its appeal. It sounds like flowing water: the soft O, the liquid nd, the final syllable that trails away. It suits a child born near the sea or given to dreaminess, and it carries a literary and mythological depth that rewards curiosity.