The daughters and wives of Athenian citizens were sheltered from men and most serious education* at least partly in order to assure their suitability as citizen wives. Adult female companionship at drinking parties (the famous symposium) could be supplied by a high priced callgirl, or hetaira. Such women might be accomplished musicians, rich, well-educated, and agreeable companions. Pericles' mistress, Aspasia of Miletus, may have been doomed to become an hetaira because she wasn't a native citizen of Athens and therefore unable to marry an Athenian citizen, but her life was probably the richer for it. Other hetairai (hetairai is a plural form of hetaira) provided funds for civic improvements.
"These women were essentially sexual entertainers and often had artistic skills. Hetairai had physical beauty but also "had intellectual training and possessed artistic talents; attributes that made them more entertaining companions to Athenian men at parties than their legitimate wives."
www.perseus.tufts.edu/classes/JKp.html The Representation Of Prostitutes Versus Respectable Women On Ancient Greek Vases
* See Daughters of Demeter for exceptions:
Women in Athens, for example, though not trained in athletics, seem nevertheless to have had opportunities for sport and exercise. And it is certain that, among the wealthy, at any rate, they learned to read and gathered in private homes to share music and poetry.