What is X?
X is a letter, a sound, a word, a symbol. X is the unknown. It can be sleek and edgy; it can be religious.
For just a simple shape of two crossed lines, X is a lot of things.
"I might say that it has the most vibes" of all the letters, says Danny Bate, a linguist and author of the book Why Q Needs U. "The most diverse range of vibes."
For this edition of Word of the Week, we're stripping things down and getting xtreme with the letter X.
Thanx to the Greeks
X has its origins in Greek, going back to around 800 B.C., Bate says. It's used in one dialect for a kʰ sound (similar to how Scots would say loch) and in another dialect for two sounds combined: ks. This second, ks, version makes its way to the Romans and their Latin, which is where the English alphabet comes from.
In Latin and English, the two sounds — ks — can be at the end of a syllable but not the beginning, Bate says. Consequently, very few English words start with X. Those that do, such as "xylophone" or "xenophobia," come from Greek.
"I think that fact that it is an oddball, it stands for two sounds, which is odd in the context of the alphabet, and it can't begin many words … gives it some of its mysticism," he says. X is present in Old English, Middle English and modern English, but X "always kind of has to fight to be used," because it's possible to make the same sound with other letters — cs, for example.
X was one of the letters Benjamin Franklin proposed getting rid of in his phonetic alphabet idea, because he thought it was redundant.
"It doesn't fit the way the other letters do. It doesn't have quite the identity as a letter sound in our words, in English," says Douglas Harper, founder and editor of Etymonline.com, an etymology dictionary. Consequently, "it's available for other things."
X is an old symbol
X can have meaning divorced from its use as an English letter.
The simple two crossed lines create a "particularly strong image," says Harper. "It's a very vivid letter. I mean, it's why you use X when you don't know how to sign your name — you put an X. The X marks on the old liquor barrels that indicated the strength and quality of it. It's a letter that can work as well in an illiterate culture as a literate one, just because of the look of it."
The ability of X to be its own symbol may also relate to its history as a Roman numeral for the number 10, says Bate. The system for counting likely predates Roman writing, he says. It started with a system of straight lines (now an I). Lines were crossed diagonally at 10, making an X.
"Roman numerals look like letters, but that is actually, by and large, accidental," Bate says. "That's a separate thing, where the symbols have merged and become more alike."
The Romans weren't known just for their numerals. They employed X's for a more gruesome purpose. Although crucifixions are usually associated with a T-shaped cross, St. Andrew the apostle was said to have been crucified on a cross shaped like an X.
And the use of Xmas to refer to Christmas is older than you might think. "X represents the first letter of the word Christós [Χριστός] in Greek," says etymology writer Jess Zafarris, author of the book Useless Etymology. "And so X was used as an abbreviation in words such as Christian and Christmas, Xmas and Xtian, quite early," at least going back to the 11th century, she says.
You're X'd
Some of X's mystique could trace to algebra, where it signifies an unknown variable. The 17th-century philosopher and mathematician René Descartes played a big role here. He used a, b and c to represent known quantities and x, y and z for things unknown.
"From that point forward, it kind of became the universal symbol for an unknown variable, especially in algebra and geometry," Zafarris says. "Once mathematics turned X into a symbol for the unknown, it became a symbol for the unknown in many contexts."
Writers began using X as a placeholder for unnamed people or unknown elements. "In the 19th century, it had become basically a common shorthand for any unknown thing," she says.
The U.S. military referred to documents about unidentified remains of service members who were killed in World War II as "X-files."
X as an unknown gives it a mysterious cool factor not enjoyed by the other letters. For example, in the late 1970s, a punk band from Los Angeles decided to go with a short name: X.
Singer Exene Cervenka said in an email that the name came when she and bassist John Doe were driving in West Hollywood and saw band names on a venue's marquee. "I said that it was so silly to name a band at all. Why did a band have to be The Something or Others? I said if I had a band, I'd just put a big black X up there." Could a single other letter have the same swagger?
Bate mentions the singing competition show The X Factor. "They chose that name because to have the 'X factor' was to have something special," he says. "It's the certain something, it's the special, it's the thing that can't be named."
X can also be a symbol of independence and defiance. In Washington, D.C., a punk youth movement emerged in the early 1980s that rejected drugs and alcohol. Adherents of the straight edge subculture would draw large X's on their hands.
By the 1940s, X was also used as a verb, meaning to cross out with an X, says Harper.
"You're X'd — get out of my life," sang the D.C. group The Faith in 1982.
Capitalism comes for X
The distinct slashes and rarity of X in English usage contribute to its commercial appeal.
"Part of the reason, probably, commercial advertisements started to use X at the end of words for -cks: It jumps out on the page," says Harper. Kleenex, Terminix, Xerox, the last one being "the ultimate product name," he says.
"It's also got the association with that Latin prefix ex that meant 'out of' and 'from,' but it came to mean 'completely.' And eventually it twists around to mean 'without.' "
After the Motion Picture Association of America implemented a rating system in the 1960s, the pornography industry took the X category that designated adult content and went into overdrive: XX and XXX became marketing points for advertising extreme sexual content.
More recently, X has been embraced in the tech world: Fields such as user experience and customer experience are known as UX and CX, respectively, using an X rather than an E for "experience."
There are, of course, X number of other associations for X — too many to examine here.
"X feels like it wants to break out. It wants to be a star somehow," Harper says. "It's not allowed to start any words in English except exotic ones. But it's fighting to be seen somehow. You got to root for X."
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