"Ordination" comes from the Latin word ordinatio, which means to incorporate someone into an order.
In the Sacrament of Holy Orders, a man is incorporated into the priesthood of Christ, at one of three levels: the episcopate, the priesthood, or the diaconate.
The priesthood is the vehicle by which God, through His Son, chose to maintain the regular flow of His grace and blessings through the sacraments.
The priest, through this sacrament of Holy Orders, offers sacrifice to God (through the Mass); forgives sins (through the Sacrament of Reconciliation); assists the sick according to the will of God (through the Sacrament of Anointing); welcomes new people into God's community the Church (through Baptism) and cements with the love of God the union of man and woman in marriage (through the Sacrament of Matrimony).
The sacrament is that which guarantees the on-going life of the church - the Body of Christ. Holy Orders - maintains that relationship with God that is the right and privilege of His people. Any man interested in discerning the Priesthood should contact the pastor or the diocesan director of vocations.