(From Old Italian) A woman prostitute, especially one whose clients are members of a royal court or men of high social standing.
Essentially, there were two types of courtesans. In one category were the courtesans known (in Italy) as the cortigiana onesta, or the honest courtesan, who were cast as intellectuals. In the other were the cortigiana di lume, which designated a lower-class of courtesan. Although the latter were still considered better than the average prostitute, the former were the ones most often romanticized and treated more or less equal to women of royalty. It is with this type of courtesan that the art of courtisanerie is best associated.
The cortigiana onesta were usually well-educated and worldly (sometimes even more so than the average upper-class woman), and often held simultaneous careers as performers or artists. They were typically chosen on the basis of their "breeding"--social and conversational skills, intelligence, common sense, and companionship--as well as their physical attributes. It was usually their wit and personality that set them apart from regular women. They were prostitutes in the sense that sex was one of their obligations, but unlike the average prostitute, sex constituted only a facet of the courtesan's array of services. For example, they were expected to be well-dressed and ready to engage in a variety of topics ranging from art to music to politics.
Son: Ohhh shit, dad!! I just found out that mom is a hooker
Dad: No, son. Ur mom is a cortigiana onesta!!! Not a hooker!!