The Sacrament Of The Eucharist
Catechism-1324: The Eucharist is "the source and summit of the Christian life"
What Is This Sacrament Called?
Catechism-1328: EUCHARIST
because it is an action of thanksgiving to God.
Catechism-1329: THE LORD'S SUPPER
because of its connection with the supper which the Lord took with his disciples on the eve of his Passion and because it anticipates the wedding feast of the Lamb in the heavenly Jerusalem.
Catechism-1330: THE MEMORIAL OF THE LORD'S PASSION AND RESURRECTION
The Holy Sacrifice, because it makes present the one sacrifice of Christ the Savior and includes the Church's offering.
HOLY SACRIFICE OF THE MASS
"sacrifice of praise," spiritual sacrifice, pure and holy sacrifice are also used since it completes and surpasses all sacrifices of the Old Covenant.
BLESSED SACRAMENT
because it is the Sacrament of sacraments.
Catechism-1331: HOLY COMMUNION
because by this sacrament we unite ourselves to Christ, who makes us shares in his Body and Blood to form a single Body, the body of Christ.
Catechism--1332: HOLY MASS
because of the liturgy in which the mystery of salvation is accomplished concludes with the sending forth of the faithful, so that they may fulfil God's will in their daily lives.
John 6:48-56
I am the bread of life. ...This is the bread that comes down from heaven, so that one may eat of it and not die. I am the living bread that came down from heaven. Whoever eats of this bread will live forever: and the bread that I will give for the life of the world is my flesh. " The Jews then disputed among themselves, saying "How can this man give us his flesh to eat?" So Jesus said to them, "Very truly, I tell you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you. Those who eat my flesh and drink my blood have eternal life, and I will raise them up on the last day; for my flesh is true food and drink my blood abide in me, and I in them.