Catechism of the Catholic Church
“The inexhaustible richness of this sacrament is expressed in the different names we give it. Each name evokes certain aspects of it. It is called:
The Holy Sacrifice, because it makes present the one sacrifice of Christ the Savior and includes the Church’s offering. the terms holy sacrifice of the Mass, ‘sacrifice of praise,’ spiritual sacrifice, pure and holy sacrifice are also used, since it completes and surpasses all the sacrifices of the Old Covenant.”
Source: Catechism of the Catholic Church #1328-30