Concubine
A concubine was a woman in a relationship with a man with no prospect of marriage.

At the beginning of the Klingon , a concubine named Karana was given the name and title of Shenara, daughter of Emperor  of the Third Dynasty. ()

In 2153, Zjod attempted to sell Jonathan Archer and Malcolm Reed a "quite skilled" Nuvian concubine. ()

In the mirror universe, the Denobulan  turned against  for the prospect of acquiring some concubines.  promised him he could choose as many as he wished. ()

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Societal classifications