Noun
(historical) Any of the autonomous tribes and city states of the Italian Peninsula in permanent military alliance with the Roman Republic until the Social War of 91–88 BC.
An associate; a fellow of an academy, etc.
(sociology) According to Gilles Deleuze, a social body that takes credit for production.
Source: en.wiktionary.orgThe meaning of the word comes from the suffix "-ology", which means "study of", derived from Greek, and the stem "soci-", which is from the Latin word socius, meaning "companion", or society in general. Source: Internet
He has authority over all Jesuits and ministries in his area, and is assisted by a socius, who acts as a sort of secretary and chief of staff. Source: Internet