CCC 1360
Christian Mystery›SECTION TWO THE SEVEN SACRAMENTS OF THE CHURCH›CHAPTER ONE THE SACRAMENTS OF CHRISTIAN INITIATION›V. The Sacramental Sacrifice Thanksgiving, Memorial, Presence
The Eucharist is a sacrifice of thanksgiving to the Father, a blessing by which the Church expresses her gratitude to God for all his benefits, for all that he has accomplished through creation, redemption, and sanctification. Eucharist means first of all "thanksgiving."