III. The Three Degrees of the Sacrament of Holy Orders

From The Catechism of the Catholic Church

1554
“The divinely instituted ecclesiastical ministry is exercised in different
degrees by those who even from ancient times have been called bishops, priests,
and deacons.”³² Catholic doctrine, expressed in the liturgy, the
Magisterium, and the constant practice of the Church, recognizes that there are
two degrees of ministerial participation in the priesthood of Christ: the
episcopacy and the presbyterate . the diaconate is intended to help and serve
them. For this reason the term sacerdos in current usage denotes bishops and
priests but not deacons. Yet Catholic doctrine teaches that the degrees of
priestly participation (episcopate and presbyterate) and the degree of service
(diaconate) are all three conferred by a sacramental act called
“ordination,” that is, by the sacrament of Holy Orders:

PART TWO: THE CELEBRATION OF THE CHRISTIAN MYSTERY

SECTION TWO THE SEVEN SACRAMENTS OF THE CHURCH
- CHAPTER THREE THE SACRAMENTS AT THE SERVICE OF COMMUNION
  - ARTICLE 6 THE SACRAMENT OF HOLY ORDERS
    - III. The Three Degrees of the Sacrament of Holy Orders

From The Catechism of the Catholic Church – rosary.team