What is the Lords Supper?:
The last meal which Jesus shared with his disciples is called the Lords Supper by Christians. In 1 Corinthians 11:20, Paul refers to the supper of the Lord, the only place in the Bible where this name is used. The gospels disagree on whether it was a Passover meal or not, but they are in agreement that it is supposed to represent an intimate fellowship between Jesus and his followers not just his disciples at the time, but with Christians today through the mass celebration.
The Gospels & the Lords Supper:
John doesnt mention this event at all and the three synoptic gospels disagree on just about all the details. It appears that there are two traditions, one used by Mark (and followed by Matthew) and one used by Luke; there is no consensus about which is older or right. Some think that the descriptions of the Lords Supper were based upon later Christian liturgies and have no historical basis at all. The heavy theological elements are likely creations of the later church.
Early Christianity & the Lords Supper:
It appears that the earliest Christians didnt celebrate the Lords Supper merely to reaffirm a connection to Jesus, but also as part of strong eschatological beliefs. Early Christians firmly believed that the world would end soon and the eucharistic bead and wine was thought to confirm their inclusion with the saved when Jesus returned to judge the wicked.
What is Eucharist?:
The word eucharist is a Greek term which means, most broadly, thanksgiving. In the New Testament it is used for prayer in general, but preferably any prayer giving thanks to God. More specific usage includes a thanks given before a meal this is why it became the term used to describe the Lords Supper at which Jesus gave his last message to his disciples and established the tradition of eating bread and wine in rememberance of him and as if they were his own body and blood.
What is Mass?:
A mass is any public celebration of the Eucharist in the Roman Catholic Church and some Protestant churches. The word mass stems from the Latin term missa, the feminine past participle of mittere, which means to send away, dismiss.
What is Transubstantiation?:
In Catholicism, transubstantiation is the idea that, during the eucharist, the substance of the bread and wine change in to the substance of the body and blood of Christ. Accidents taste, texture, appearance, etc. remain the same, but the essence (underlying reality) changes. This doctrine was first described during the Lateran Council of 1215 and defined formally during the Council of Trent in 1551. It was rejected by Protestant reformers who argued that the transformation is symbolic.
What is Consubstantiation?:
Consubstantiation is the Lutheran doctrine that, in the eucharist, Jesus Christ is only present mystically, right alongside the elements of bread and wine. Thus, unlike the Catholic dogma of transubstantiation, the essences of bread and wine are not transformed.
What is Communion?:
In Christianity, communion refers to the act of receiving the eucharist at a formal ceremony. For Catholics in particular, it is a sacrament which is first received when they reach the age of seven and have had their first Confession. Non-Catholics are not allowed to receive communion in a Catholic Church and Catholics are permitted (but not required) to receive communion as often as once every day.