'aubain' originates from Old French (also seen as 'aubaine' or 'aubain'), where it was used to denote a foreigner or the concept of a sovereign's claim over a foreigner's property.

'aubain' was used in Old French and entered Middle English legal and administrative records with the same spelling; over time the term became rare in ordinary English but persisted in legal-historical contexts (often in reference to the 'droit d'aubaine').

Initially it denoted simply a 'foreigner'; later its usage in law became specialized to include the sovereign's right to take the movable goods of foreigners who died in the realm.