Does Xmas leave Christ out of Christmas?
Xmas has been used for hundreds of years in religious writing, where the X is understood to represent a Greek chi, the first letter of CrstoV, “Christ”; in this use it is parallel to other forms like Xtian, “Christian.” But the letter X, or especially x, is nowadays more frequently interpreted as a mathematical variable than as a Greek letter, as indicated by the common pronunciation of the form Xmas as ( ).
