aubaine n.

"right of French kings to claim the property of a non-naturalized stranger who dies in their realm," 1727, from French (droit d'aubaine), from aubain "stranger, non-naturalized foreigner" (12c.), which is of unknown origin; perhaps from Medieval Latin Albanus, but the sense is obscure. Klein suggests Frankish *alibanus, literally "belonging to another ban." Abolished 1819.