Through the Sacrament of Holy Orders, the mission of the Church, which was entrusted two thousand years ago by Christ to the Twelve Apostles, is carried out by men all over the world today. There are three degrees of ordination: the diaconate, the presbyterate (priesthood), and the episcopate (the order of bishops). It is the mission of these men to serve the children of God in a unique way, fulfilling Jesus' instruction at the Last Supper: "That you also should do as I have done to you." (John 13:15)
"The word order in Roman antiquity designated an established civil body, especially a governing body. Ordinatio means incorporation into an ordo. In the Church there are established bodies which Tradition, not without a basis in Sacred Scripture, has since ancient times called taxeis (Greek) or ordines. And so the liturgy speaks of the ordo episcoporum, the ordo presbyterorum, the ordo diaconorum. Other groups also receive this name of ordo; catechumens, virgins, spouses, widows,....
"Integration into one of these bodies in the Church was accomplished by a rite called ordinatio, a religious and liturgical act which was a consecration, a blessing or a sacrament. Today the word ordination is reserved for the sacramental act which integrates a man into the order of bishops, presbyters, or deacons, and goes beyond a simple election, designation, delegation, or institution by the community, for it confers a gift of the Holy Spirit that permits the exercise of a sacred power (sacra potestas) which can come only from Christ himself through his Church. Ordination is also called consecratio, for it is a setting apart and an investiture by Christ himself for his Church. The laying on of hands by the bishop, with the consecratory prayer, constitutes the visible sign of this ordination."
~The Catechism of the Catholic Church
Vocational discernment is the process in which men or women discern, or recognize, their vocation in the Church. The four vocations are the married life, single life, religious life, and ordained life. There are numerous resources available for both men and women who are open to find where Our Lord is calling them in this life.