When I hear the word concubine, my mind immediately goes to historical contexts such as emperors’ harems. However, the term can also refer to a partner in a sexual relationship where the couple is not married. Originally borrowed into English in the late thirteenth century from Anglo-Norman with this singular definition, it has since evolved. The word originates from the Latin verb concumbere, which meant “to lie with” and is made up of con- meaning “with” and cubare meaning “to lie down”. The prefix con-, derived from the Proto-Italic and earlier Latin word cum, traces back to the Proto-Indo-European root kom, which can also mean “next to”. The root of cubare (also the source of English words like cubicle and cubit) can be traced back to a Proto-Indo-European word that sounds like kewb or kub, although its exact meaning is uncertain.