Mass is the main Eucharistic liturgical service in many forms of Western Christianity. The term Mass is commonly used in the Catholic Church, Western Rite Orthodoxy, Old Catholicism, and Independent Catholicism. The term is also used in some Lutheran churches, as well as in some Anglican churches, and on rare occasion by other Protestant churches.
Other Christian denominations may employ terms such as Divine Service or worship service (and often just "service"), rather than the word Mass. For the celebration of the Eucharist in Eastern Christianity, including Eastern Catholic Churches, other terms such as Divine Liturgy, Holy Qurbana, Holy Qurobo and Badarak (or Patarag) are typically used instead.
The English noun Mass is derived from the Middle Latin missa. The Latin word was adopted in Old English as mæsse (via a Vulgar Latin form *messa), and was sometimes glossed as sendnes (i.e. 'a sending, dismission').
The Latin term missa itself was in use by the 6th century. It is most likely derived from the concluding formula Ite, missa est ("Go; the dismissal is made"); missa here is a Late Latin substantive corresponding to classical missio.
Historically, however, there have been other etymological explanations of the noun missa that claim not to derive from the formula ite, missa est. Fortescue (1910) cites older, "fanciful" etymological explanations, notably a latinization of Hebrew (מַצָּה) "unleavened bread; oblation", a derivation favoured in the 16th century by Reuchlin and Luther, or Greek μύησις "initiation", or even Germanic mese "assembly". The French historian Du Cange in 1678 reported "various opinions on the origin" of the noun missa "Mass", including the derivation from Hebrew (Missah, id est, oblatio), here attributed to Caesar Baronius. The Hebrew derivation is learned speculation from 16th-century philology; medieval authorities did derive the noun missa from the verb mittere, but not in connection with the formula ite, missa est.