Holy Orders

The sacrament of holy orders in the Catholic Church includes three orders: bishops, priests, and deacons, in decreasing order of rank, collectively comprising the clergy. In the phrase “holy orders”, the word “holy” means “set apart for a sacred purpose”. The word “order” designates an established civil body or corporation with a hierarchy, and ordination means legal incorporation into an order. In context, therefore, a group with a hierarchical structure that is set apart for ministry in the Church.

For more information, please see the official USCCB website:
https://www.usccb.org/prayer-and-worship/sacraments-and-sacramentals/holy-orders