Hetaira (explic.)

"one of a class of professional independent courtesans of ancient Greece who, besides developing physical beauty, cultivated their minds and talents to a degree far beyond that allowed to the average Attic woman. Usually living fashionably alone, or sometimes two or three together, the hetairai enjoyed an enviable and respected position of wealth and were protected and taxed by the state. Though they were generally foreigners, slaves, or freedwomen, their freedom was greater than that of the married woman, who was bound to seclusion. That their homes were frequented by married men was not censured by society. (...)"

Britannica online