The word "Christ" and its compounds, including "Christmas", have been abbreviated for at least the past 1,000 years, long before the modern "Xmas" was commonly used. "Christ" was often written as "XP" or "Xt"; there are references in the Anglo-Saxon Chronicle as far back as 1021 AD. This X and P arose as the uppercase forms of the Greek letters χ and ρ), used in ancient abbreviations for Χριστος (Greek for "Christ") (see Labarum), and are still widely seen in many Eastern Orthodox icons depicting Jesus Christ.
Many people believe that the term is part of an effort to "take Christ out of Christmas" or to literally "cross out Christ"; it is also seen as evidence of the secularization of Christmas or a vehicle for pushing political correctness, or as a symptom of the commercialization of the holiday (as the abbreviation has long been used by retailers).
The occasionally felt belief that the "X" represents the cross Christ was crucified on has no basis in fact; regardless, St Andrew's Cross is X-shaped, but Christ's cross was probably shaped like a T or a . Indeed, X-as-chi was associated with Christ long before X-as-cross could be, since the cross as a Christian symbol developed later. (The Greek letter Chi Χ stood for "Christ" in the ancient Greek acrostic ΙΧΘΥΣ ichthys.) While some see the spelling of Christmas as Xmas a threat, others see it as a way to honor the martyrs. The use of X as an abbreviation for "cross" in modern abbreviated writing (e.g. "Kings X" for "Kings Cross") may have reinforced this assumption.
In ancient Christian art χ and χρ are abbreviations for Christ's name. In many manuscripts of the New Testament and icons, X is an abbreviation for Christos, as is XC (the first and last letters in Greek, using the lunate sigma); compare IC for Jesus in Greek. The Oxford English Dictionary documents the use of this abbreviation back to 1551, 50 years before the first English colonists came to North America and 60 years before the King James Version of the Bible was completed. At the same time, Xian and Xianity were in frequent use as abbreviations of "Christian" and "Christianity"; and nowadays still are sometimes so used, but much less than "Xmas". The proper names containing the name "Christ" other than aforementioned are rarely abbreviated in this way (e.g. Hayden Xensen for the actor name "Hayden Christensen"). Pop artist Christina Aguilera is known to spell her first name as 'Xtina'.
This apparent usage of "X" to spell the syllable "kris" (rather than the sounds "ks") has extended to "xtal" for "crystal", and on florists' signs "xant" for "chrysanthemum" (though these words are not etymologically related to "Christ"; "crystal" comes from a Greek word meaning "ice", and "chrysanthemum" from Greek words meaning "golden flower", while "Christ" comes from a Greek word meaning "anointed").
In the animated television show Futurama, which is set in the 31st century, Xmas is the official name for the day formerly known as Christmas (which has become an "archaic pronunciation").
