Origin of the name JULIANUS.
Etymology of the
Meaning of the baby name JULIANUS.
the Roman gens name Julian
(q.v.), meaning "downy bearded."
family that in turn mounted the imperial throne was supposed to be
adopted into the Julian gens, all bore its appellation; and thus it was
that out of the huge stock of nomina that had accumulated in the family
of Constantius, the apostate bore by way of distinction the adoptive
form of Julianus. (History of Christian Names, Yonge, 1884)