The elements of the Eucharist, bread (leavened or unleavened) and wine (or grape juice), are consecrated on an altar (or table) and consumed thereafter. Communicants (that is, those who consume the elements) may speak of "receiving the Eucharist", as well as "celebrating the Eucharist". Christians generally recognize a special presence of Christ in this rite, though they differ about exactly how, where, and when Christ is present. While all agree that there is no perceptible change in the elements, Roman Catholics believe that their substances actually become the body and blood of Christ (transubstantiation). Lutherans believe the true body and blood of Christ are really present "in, with, and under" the forms of the bread and wine (sacramental union or, by some, consubstantiation). Reformed Christians believe in a real spiritual presence of Christ in the Eucharist. Others, such as the Plymouth Brethren, take the act to be only a symbolic reenactment of the Last Supper.
In spite of differences among Christians about various aspects of the Eucharist, there is, according to the Encyclopædia Britannica, "more of a consensus among Christians about the meaning of the Eucharist than would appear from the confessional debates over the sacramental presence, the effects of the Eucharist, and the proper auspices under which it may be celebrated."
The Greek noun εὐχαριστία (eucharistia), meaning "thanksgiving", is not used in the New Testament as a name for the rite; however, the related verb is found in New Testament accounts of the Last Supper, including the earliest such account:
For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread, and when he had given thanks (εὐχαριστήσας), he broke it, and said, "This is my body which is for you. Do this in remembrance of me". (1 Corinthians 11:23–24)
The term "Eucharist" (thanksgiving) is that by which the rite is referred by the Didache (late 1st or early 2nd century), Ignatius of Antioch (who died between 98 and 117) and Justin Martyr (writing between 147 and 167). Today, "the Eucharist" is the name still used by Eastern Orthodox, Oriental Orthodox, Roman Catholics, Anglicans, Presbyterians, and Lutherans. Other Protestant or Evangelical denominations rarely use this term, preferring either "Communion", "the Lord's Supper", or "the Breaking of Bread".