Wiktionary
n. A bishop who functions as another bishop's deputy where the weight of sacramental duties is too much for a single bishop. Compare coadjutor bishop.
Wikipedia
An auxiliary bishop, in the Roman Catholic Church, is an additional bishop assigned to assist a bishop in meeting the pastoral needs of his diocese. They exist in both the Latin Church and in the Eastern Catholic Churches. Auxiliary bishops are titular bishops of sees that no longer exist.
The particular duties are given by the diocesan bishop and can vary widely depending on the auxiliary bishop, the ordinary, and the needs of the diocese.
In a larger archdiocese, they might be in assigned to serve a portion of the archdiocese (sometimes called deaneries, regions, or vicariates) or to serve a particular population such as immigrants or those of a partcular heritage or language.
Canon law requires that the diocesan bishop appoint each auxiliary bishop as vicar general or episcopal vicar of the diocese.
Usage examples of "auxiliary bishop".
They cant all be like Arilan, I suppose: auxiliary bishop at thirty-five, and with his own see before he was forty.
They can't all be like Arilan, I suppose: auxiliary bishop at thirty-five, and with his own see before he was forty.
I told Bradene, before I approved your election as an auxiliary bishop, that I wouldn't allow you to accept any titular bishopric besides Rhemuth or possibly Valoret.
Still, Brion's appointment of a very junior auxiliary bishop to his privy council must have reflected a close personal trust and friendship.
The young auxiliary bishop of Rhemuth had had to put up with what he considered fanatic foolishness far too many times to be impressed just because Loris was Primate of Gwynedd.
Roland, Bishop-auxiliary Bishop of Valoret, and Anscom's subordinate.