The word "Christmas" is a bit long. Far easier and faster to scrawl "Xmas" on your holiday cards and notes. But if you do, be prepared for a backlash among some who will insist that in doing so, you're slamming Christ. As in Jesus Christ, the baby born in a manger on Dec. 25 (allegedly). The little guy who is responsible for everything Christmas, Santa included. But how is "Xmas" a dis?
Some argue the abbreviation "Xmas" was created by religion haters. If you write "Xmas," they assert, you're helping to commercialize the holiday and wipe away its true meaning. But they are misinformed. The term "Xmas" came about centuries ago. The first letter in the Greek word for "Christ" is "Chi," and a capital Chi is written as "X." So "Xmas" is an old, respectable abbreviation for "Christmas" [source: Mikkelson].
So, while some may intentionally scrawl "Xmas" as a jab at religion, its original usage was perfectly acceptable to the faithful.