The Eucharist is another name for Holy Communion. The term comes from the Greek by way of Latin, and it means "thanksgiving." It is used in three ways: first, to refer to the Real Presence of Christ; second, to refer to Christ's continuing action as High Priest (He "gave thanks" at the Last Supper, which began the consecration of the bread and wine); and third, to refer to the Sacrament of Holy Communion itself.
The Catechism of the Catholic Chruch (1324-1327), states that, "The Eucharist is "the source and summit" of the Christian life. The other sacraments, and indeed all ecclesiastical ministries and works of the apostolate, are bound up with the Eucharist and are oriented toward it. For in the blessed Eucharist is contained the whole spiritual good of the Church, namely Christ himself, our Pasch. The Eucharist is the efficacious sign and sublime cause of that communion in the divine life and that unity of the People of God by which the Church is kept in being. It is the culmination both of God's action sanctifying the world in Christ and of the worship men offer to Christ and through him to the Father in the Holy Spirit. Finally, by the Eucharistic celebration we already unite ourselves with the heavenly liturgy and anticipate eternal life, when God will be all in all. In brief, the Eucharist is the sum and summary of our faith: Our way of thinking is attuned to the Eucharist, and the Eucharist in turn confirms our way of thinking."