|Noah Webster's Dictionary|
1. (n.) The cohabiting of a man and a woman who are not legally married; the state of being a concubine.
2. (n.) A plea, in which it is alleged that the woman suing for dower was not lawfully married to the man in whose lands she seeks to be endowed, but that she was his concubine.
Int. Standard Bible Encyclopedia
Concubinage (1 Occurrence)
Ezekiel 23:20 And she doted upon their paramours, whose flesh is as the flesh of asses, and whose issue is like the issue of horses. (See JPS)