Hetaerism

Noun

1. A theoretical early state of human society (as postulated by 19th-century anthropologists) which was characterized by the absence of the institution of marriage in any form, and where women were the common property of their tribe, and the children never knew their fathers.
2. An Ancient Greek custom according to which a man's wife was forbidden to accompany him to many public events, including the banquets or symposia which made up a large part of Greek social life, and where men sought out the company of courtesans or hetaerae instead.