Why Is There an X in Xmas? Isn't It Sacrilegious?

Some Christians complain that the abbreviation 'Xmas' for Christmas is part of a move to secularize the holiday, to take the Christ out of Christmas, but this isn't really justified.

It is said that when Emperor Constantine had his great vision that caused him to convert to Christianity, he saw the Greek letters Chi and Rho intertwined. Chi is written as an 'X' and Rho is written as a 'P', but they are the first two letters of the Greek word Christ 'savior'. 'XP' is sometimes used to stand for Christ. Sometimes 'X' is used alone. This is the case in the Chi (X) abbreviation for Christ in Xmas. Thus, Xmas is not directly a way of secularizing the holiday, but since 'X' is not Chi in English, we read the word as X-mas and see no connection with Christ.

Sacrilegious, an adjective some have applied to the Xmas spelling, is easy to misspell. It looks as though it should be "sac-" plus the word religious, but it isn't. Instead, according to the Online Etymology Dictionary, it comes from the Latin phrase sacrum legere: "to steal sacred things."