The Collaborative International Dictionary of English v.0.48:

Paterfamilias \Pa`ter*fa*mil`i*as\, n.; pl. Pateresfamilias.
   [L., fr. pater father + familias, gen. of familia family.]
   (Rom. Law)
   The head of a family; in a large sense, the proprietor of an
   estate; one who is his own master.
   [1913 Webster]