Many listeners have asked about the origin, meaning, and appropriateness of Xmas, the abbreviation for Christmas.

Retailers have long been accused of secularizing Christmas by using Xmas in signs and advertisements; therefore, I suspect many of you will be surprised to learn that Xmas has a religious origin.

In Greek, the letter chi is written as an X, and chi is the first letter of the Greek word for Christ. Greeks sometimes abbreviated Christ as X, and around 300 AD, the Roman emperor Constantine I started using the symbol XP to symbolize Christ. In that use, XP stands for the Greek letters Chi-Rho, which are the first two letters of the Greek word for Christ. Constantine’s symbol superimposed the letters in a stylized way and it’s been drawn in many different ways over the years, so although you’ve probably seen the symbol, you may not have realized that it was two letters.

Xmas is much newer than the XP symbol, but it’s not the result of recent commercialization. The Oxford English Dictionary shows 1551 as the first year Xmas was used to mean Christmas in English.

As for appropriateness, Xmas may have a religious origin and fit better on signs, but many people — both those who use Xmas and those who complain about its use — are unaware of its religious origin. Some style guides recommend against using Xmas, and if you do choose to use it, you should know that some people won’t be happy.

Labarum image from Nick Thompson at Flick. CC BY-NC-SA 2.0