Fake Christmas lies [closed]

Wikipedia has the answer for you:

"Christmas" is a compound word originating in the term "Christ's Mass". It is derived from the Middle English Cristemasse, which is from Old English Crīstesmæsse, a phrase first recorded in 1038. Crīst (genitive Crīstes) is from Greek Khrīstos (Χριστός), a translation of Hebrew Māšîaḥ (מָשִׁיחַ), "Messiah"; and mæsse is from Latin missa, the celebration of the Eucharist. The form "Christenmas" was also historically used, but is now considered archaic and dialectal; it derives from Middle English Cristenmasse, literally "Christian mass". "Xmas" is an abbreviation of Christmas found particularly in print, based on the initial letter chi (Χ) in Greek Khrīstos (Χριστός), "Christ", though numerous style guides discourage its use; it has precedent in Middle English Χρ̄es masse (where "Χρ̄" is an abbreviation for Χριστός).

~ http://en.wikipedia.org/wiki/Christmas#Etymology

The X has nothing to do with a cross.