"Mass" is one of the names by which the sacrament of the Eucharist is called in the Roman Catholic Church: others are "Eucharist", the "Lord's Supper", the "Breaking of Bread", the "Eucharistic assembly (synaxis)", the "memorial of the Lord's Passion and Resurrection", the "Holy Sacrifice", the "Holy and Divine Liturgy" and "Holy Communion". The term "Mass" is one of the most common in connection with Catholic Latin liturgical rites. It is used also of similar celebrations in Old Catholic Churches, in the Anglo-Catholic tradition of Anglicanism, in Western Rite Orthodox Churches, and in some Lutheran churches. But most Protestants prefer terms other than "Mass", which to them denotes Roman Catholic ritual and understanding of the Eucharist. For the celebration of the Eucharist in Eastern churches, including those in full communion with the Holy See, other terms such as the Divine Liturgy, the Holy Qurbana and the Badarak are normal.

For information on the theology of the Eucharist and on the Eucharistic liturgy of other Christian denominations, see "Eucharist" and "Eucharistic theology".