BISHOP. A successor of the Apostles who has received the fullness of Christ's priesthood. His most distinctive power, that of ordaining priests and other bishops, belongs uniquely to a bishop. Moreover, m spite of some disputed cases in history, it is highly probable that a priest would not be authorized by the Holy See to ordain another priest. A priest certainly cannot consecrate a bishop.
In the ordination of a bishop the "matter" is the imposition of hands on the head of the bishop-elect by the consecrating bishops, or at least by the principal consecrator, which is done in silence before the consecratory prayer; the "form" consists of the words of the consecratory prayer, of which the following pertains to the essence of the order, and therefore are required for the validity of the act: "Now pour out upon this chosen one that power which flows from you, the perfect Spirit whom He gave to the apostles, who established the Church in every place as the sanctuary where your name would always be praised and glorified." (Etym. Greek episkopos, a bishop, literally, overseer.)
Again, I would dispute Father's definition of the 'matter' of the Sacrament. He also omits the fact that Bishops are the ordinary governors of Dioceses.