(Lat. papa, ‘father’).
In the W. Church the title is now restricted to the Bp. of Rome in respect of his capacity as supreme head on earth of the universal Church; in early times it was used of any bishop. In the E. it was apparently confined to the Patr. of Alexandria, who is still so styled, but from the 6th cent. the chancery at Constantinople normally kept it for the Bp. of Rome.