I always think of the word concubine in historical terms. To me, it brings to mind emperors' harems, but apparently it can also refer to a partner in any sexual relationship where the couple is unmarried. This was the sole definition when the term was borrowed into English in the late thirteenth century from Anglo-Norman, but it has since evolved. That comes from the Latin verb concumbere, which meant "to lie with" and was composed of con-, meaning "with", and cubare, meaning "to lie down". Con-, through Proto-Italic and the earlier Latin word cum, derives from the Proto-Indo-European root kom, which could also mean "next to". Cubare (also the etymon of English cubicle and cubit) traces to a Proto-Indo-European word sounding like kewb or kub, but definition is uncertain.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.