/kris"meuhs/ or, often, /eks"meuhs/
Christmas.
Usage . The abbreviation XMAS for Christmas dates from the mid 16th century. The X is the Greek letter chi, the initial part of a greek word ( Christos ) "Christ." In spite of a long and respectable history, today XMAS is offensive to many, perhaps because of its associations with advertising. It is not used in formal writing.