pantagamy
/panˈtaɡəmi/US. Now historical
noun
A communal system of marriage in which all the men and women of a household or community are regarded as married to each other, formerly practised by the Perfectionist community at Oneida, New York State (1848–79).
Origin
Mid 19th century; earliest use found in John Nichol (1833–1894), literary scholar and writer. From panta-, variant of panto- + -gamy.