The Eucharist is another name for Holy Communion or the Lord's Supper. The term comes from the Greek by way of Latin. It means "thanksgiving." When the priest consecrates the bread and wine, its substance becomes the body and blood of Christ. This process is known as transubstantiation.
According to the New Testament, the Eucharist was instituted by Jesus Christ during his Last Supper. Days before his crucifixion he shared a final meal of bread and wine with his disciples during the Passover meal. Jesus instructed his followers that the bread was "my body" and the wine was "his blood." He commanded his followers to eat these and "do this in memory of me."
"And he took bread, gave thanks, broke it, gave it to them, and said, 'This is my body, which is given for you. Do this in remembrance of me.'"—Luke 22:19, Christian Standard Bible
The Eucharist is the source and summit of our Catholic faith. During mass, we experience the presence of God in four ways: