In Greek, "xmas" is commonly used as a shorthand for Christmas. The "x" in "xmas" represents the Greek letter "chi" (χ), which is the first letter of the Greek word "Christos," which means "Christ." So, "xmas" is essentially a shorter way of saying "Christ's Mass" or "Christmas." However, it's worth noting that some people prefer to use the full word "Christmas" to avoid the potential confusion or loss of meaning that may occur when using the shortened form.