the state of cohabitation of a man and a woman without the full sanctions of legal marriage. The word is derived from the Latin con (“with”) and cubare (“to lie”).

The Judeo-Christian term concubine has generally been applied exclusively to women, although a cohabiting male may also be called a concubine. In Roman law concubinage was the permanent cohabitation of a man and a woman outside of their existing formal marriages. The partners in such relationships and the offspring of their union did not have the same legal rights accorded married persons and their legitimate children. See also common-law marriage.