What's the "een" in Halloween?
1919, but it may have origins in 19c. U.S. Southern black speech. Origin unknown, suspects include Latin, Yiddish (e.g. Hebrew kol b'seder), Italian, Louisiana French (coupe-sétique), and Native American. None is considered convincing by linguists.
[1919+ fr black; origin unknown; perhaps fr Louisiana Creole French coupe-se´tique in the same sense, semantically related to cope, attested fr about 1880; perhaps fr Hebrew kol ba seder, ''all in order,'' which may have been acquired by black customers of a Jewish merchant]