Paterfamilias
Definition: the head of a family
Clearly, this is a combination of “paternal” and “family.”
Why I Looked It Up
In a discussion of William F. Buckley:
Through his longevity, sustained productivity, and public visibility, Buckley served the intellectual conservative movement as a paterfamilias.
Postscript
Added on
The role of paterfamilias comes up a lot in The First Man in Rome.