"Merry Xmas!" "Big Xmas sale!" Xmas , it appears, is firmly established as a commercialism. We tend to place it in the same class as nite and hi (for high): abbreviations contrived largely for the convenience of advertisers. But Xmas is a more interesting case. In fact, it is a classic example of a symbol firmly established for one purpose being preempted for an entirely different one.
The X in Xmas is the Greek letter chi (pronounced ky). In Greek, chi is the first letter in Christ--a point that is lost when the Greek is transliterated into English as Christos or Kristos. X (the Greek and Roman letters are identical in print) is also a symbol for the cross--a usage that survives quite independently of any religious significance in traffic signs: PED XING. But for well over 1,000 years, X, preemptively and presumptively, symbolized Christ. The Irish refused to use the Roman numeral X because it would be disrespectful to Christ. So common was the understanding of this symbol that non-Christians who wished to preserve their cultural identity took pains to avoid it. The Chinese altered their coins to remove anything resembling an X because they saw it as an inviolable symbol of the Western religion and, hence, Western influence. Early in this century, illiterate Jewish immigrants arriving at Ellis Island often refused to sign their names with an X because of its strong Christian associations.
Xmas itself has a long history as an English idiom. The Oxford English Dictionary, in about 1920, defined it simply as a "common abbreviation in writing of Christmas." The first use cited in the OED is from 1551, spelled as X'temmas. The poet Coleridge used in twice in letters, in 1799 and 1801. The last use cited in the OED is from the popular British magazine Punch in 1884. We can see the secularizing trend at work: "He's beginning Xmassing already."
The wholesale expropriation of Xmas as a commercial term, however, has been chiefly an American phenomenon. Christmas itself had rather inauspicious beginnings in this country. In 1659 the General Court of Massachusetts passed a law which imposed a fine on "anybody who is found observing, by abstinence from labor, feasting, or any other way, any such days as Christmas Day." These were Puritans, keep in mind, who were inclined to take evidence that anyone might be having a good time as a sign of "popery." While the celebration of Christmas as a holiday was widely accepted by the time of the Revolution, Christmas as a commercial holiday had to wait until after the Civil War. Gift giving, which had been a rare and personal convention at the beginning of the 19th Century, started to become a social obligation. R. H. Macy's department store in New York City stayed open until midnight on Christmas Eve for the first time in 1867. Macy's first Christmas window display appeared in 1874.
As Christmas grew into what Daniel Boorstin has called "a spectacular nationwide Festival of Consumption," Christmas advertising grew with it. But advertisers did not need to invent a new abbreviation for the nine-letter word denoting the season. They simply used one that had been around for centuries. And in less than 100 years the usage of well over 1,000 years was largely reversed. What once nearly everyone took to be a religious symbol, today nearly everyone regards as a secular symbol.
Stan Freberg did a novelty song several years ago, I think it was called "Green Christmas," in which he asked the musical question: "Who put the X in Xmas?" Well, as a matter of fact, the early Christians put the X in Xmas. What we have often done in the 20th-Century has been to take the meaning out.