(noun) the male head of a household / (noun) the father of a family / (noun) a man who originates or is a leading figure in something (as a movement, discipline, or enterprise)
Speer knew Hitler as a "solicitous paterfamilias"
In these early years of Don Carlos’s life, relations with the pater- familias were still good
He is a man of about forty, Jewish, American, pleasant-looking, a bit of a paterfamilias.
He was born in one of its North Shore suburbs; he was raised, reached adulthood, and became a paterfamilias as a “typical suburbanite.”