The name is derived from the Greek, αδελφος (adelphos), meaning “brother.”
The name was mostly notably borne by Adelphe of Metz, a 5th-century Franco-German saint, the 12th bishop of Metz.
Other forms of the name include:
Adelphos αδελφος (Greek)
Adelphus (Late Latin)
In France, the designated name-day is September 11.