Of uncertain origin. From the 18th century it is clearly used as a pet form of Ann (see Nan), but it may originally have been a similar formation deriving from the common medieval given name Annis, a vernacular form of Agnes. Nowadays it is an independent name, and was especially popular in America in the 1930s, 40s, and 50s. A meaning of the name Nancy is Grace.
English and Scottish: occupational name for a tailor, from Old French tailleur (Late Latin taliator, from taliare ‘to cut’). The surname is extremely common in Britain and Ireland, and its numbers have been swelled by its adoption as an Americanized form of the numerous equivalent European names, most of which are also very common among Ashkenazic Jews, for example Schneider, Szabó, and Portnov.