"Christmas /'krismes/ n. (also Christmas Day) annual festival of Christ's birth, celebrated
on 25 Dec.
[Old
English: related to Christ, Mass] "
- Christmas, The Oxford Dictionary of
Current English
"An annual church festival (December 25) and in some States a legal
holiday, in memory of the birth of Christ, often celebrated by a
particular church service, and also by special gifts, greetings,
and hospitality."
-
Christmas, Webster Dictionary
(http://www.webster-dictionary.net/definition/Christmas)