Holy Orders are ordained ministries such as bishop, priest, or deacon, and the sacrament or rite by which Candidates are ordained to those orders. There are two notable ways in which the sacrament of Holy Orders differs from the other sacraments.
One is the fact that Holy Orders can be administered only by a bishop. Only a bishop has the power to ordain priests. An ordinary priest cannot pass his power on to another. The second way in which Holy Orders differs from other sacraments is that Holy Orders is not received all at once.
When we are baptized, we are completely baptized by the single pouring of water. When we are confirmed, we are completely confirmed in a single ceremony. Holy Orders, however, is given by degrees, by successive steps.