concubinage
noun
con·cu·bi·nage kän-ˈkyü-bə-nij 
kən-
1
: cohabitation of persons not legally married
2
: the state of being a concubine
Word History
First Known Use
14th century, in the meaning defined at sense 1
Legal Definition
concubinage
noun
con·cu·bi·nage kän-ˈkyü-bə-nij
: the relationship between persons who are cohabiting without the benefit of marriage —used especially in the civil law of Louisiana compare common-law marriage
Note: Under Louisiana law, concubinage does not give rise to any rights in the parties to each other's property.