The word Christmas comes from Middle English Cristemasse, which in turn comes from Old English Cristes-messe, literally meaning Christ’s Mass.
Of course, we are not talking about the physical mass of Christ’s body. The origin of mass, in the Christian sense of the word, is not entirely clear. We know it comes from Latin missa, but there are several competing theories as to what missa is supposed to mean. Some scholars say it is a form of the Latin verb mittere, in which case it would mean “something that has been sent” (but it cannot refer to Christ himself because “missa” is grammatically feminine).
Others say that it is a late form of Latin missio, meaning “dismissal”. This is supported by the fact that Catholic masses are traditionally concluded with the words:
which would mean, “Go, the dismissal is made”, provided this interpretation is correct.
Yet another explanation is that it is, in fact, the Hebrew word missah, “unleavened bread”, which God commanded to be offered with the Passover sacrifice in the Exodus.
The name “Christ”
The origin of the designation Christ is also not without interest. It comes from Greek Χριστός (Christós), meaning “anointed”, which is a translation of Hebrew מָשִׁיחַ māšîaḥ (“anointed”) that has been incorporated into the English language as “messiah”. Hence, “Christ” and “Messiah” mean essentially the same, the former originating in Ancient Greek and the latter in Classical Hebrew.
Finally, we get to the word Xmas (usually pronounced the same as Christmas, but some pronounce it, rather incorrectly, as /ˈɛksməs/). Many people believe that writing “Xmas” instead of Christmas is an attempt to remove Christ from Christmas and may even consider it blasphemous.
However, “X” in “Xmas” is, in fact, not the English letter “ex”. It is an abbreviation of the Greek name of “Christ”, Χριστός (Christos), which starts with the Greek letter Chi. Abbreviating “Christ” as “X” can be traced many centuries back, with some written documents dated as early as 1100 AD.