paterfamilias, patresfamilias 1. The father of a family; male head of a household. 2. In Roman Law, the head of a family or household having the authority belonging to that position over the persons composing it; also, a person of either sex and any age who is sui juris and free from parental control. Found on http://www.wordinfo.info/words/index/info/view_unit/2572/