Catechism of the Catholic Church §1382 — excerpt
The Mass is at the same time, and inseparably, the sacrificial memorial in which the sacrifice of the cross is perpetuated and the sacred banquet of communion with the Lord's body and blood.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.