Late 19th‐century coinage, from the archaic word fay ‘fairy’. It was to some extent influenced by the revival of interest in Arthurian legend, in which Morgan le Fay is King Arthur's half-sister, a mysterious sorceress who both attempts to destroy Arthur and tends his wounds in Avalon after his last battle. She is sometimes identified with the ‘Lady of the Lake’. Between the wars the name came to prominence as that of the British actress Fay Compton (1894–1979); more recently it has been associated with the writer Fay Weldon (b. 1931).
German, Dutch, Danish, and Jewish (Ashkenazic): nickname for a tall man, from an inflected form of Lang.According to Gottschald, in the Franconian dialect of German this was also a term for an unskilled laborer (more fully, Handlanger).