A Brief History of “X”

Yesterday, Apple unveiled the iPhone 8, iPhone 8 Plus, and iPhone X, which the company is pronouncing “iPhone Ten.” Ten years ago, Apple transformed the smartphone landscape—and our very lives, for better or worse—with its first very iPhone, hence the Roman numeral X, or 10, in its new mobile moniker. Let’s take a quick look at the history of X, from its birth as a letter and numeral to its spread into everything from Jesus to algebra.

The Roman Numeral X

As noted, X corresponds to the number 10 in Roman numerals. We know the ancient Romans adapted their notational system from the Etruscans, but the deeper roots of the symbols themselves are obscure.

One theory thinks the numerals evolved out of basic tally marks. The Roman numeral I (1) was a simple notch, with every fifth one double-notched, yielding V (5) and every tenth crossed into an X (10).

Another theory thinks the numerals emerged from hand-counting. I represents one finger and V a full hand. If you hold out your hand, you can see how the gap between the thumb and index finger might resemble a V. Hold out two hands for 10 and you can imagine how two V’s, stacked on top of each other, can look like an X.

Whatever their origin, the form of the symbols were adapted to the existing letters in the Latin alphabet—which included letter X.

Roman numerals marking a seating entrance in the Coliseum (Romewise). 

The Letter X

The ancient Greeks added letter X—called chi, its 22nd letter and our 24th—when they borrowed the Phoenician alphabet. Originally, X represented a kh sound, but certain regional alphabets took to using the symbol as a convenient shorthand for frequent ks combinations in the language. The Etruscans also adopted this convention—and later the Romans, which ultimately made its way into the sound and shape of English’s own X.

The Christ X

The Greek chi is the first letter in Χριστός (Khristos), source of Christ. This epithet literally means “anointed,” a translation of the Semitic messiah; rubbing oil on heads of kings, priests, and other important figures was an ancient custom used to consecrate them.

The second letter Χριστός is rho—ρ and source of r—and together Χριστός was abbreviated to its initial in old manuscripts. This digraph became the Christogram ☧, symbolizing Jesus on various Christian materials and imagery. The shorter shorthand of X for Christ also appears in Xmas, i.e., Christmas, which has been in use since the 1500s. That letter X also resemble a cross, so central to the Christian belief system, further underscores its association with Jesus Christ.

A chi-rho Christogram from a fourth-century sarcophagus (Wikimedia Commons).

The Kiss X

For Christians, Christ—and his symbol X—evoke faith and fidelity, and apparently medieval Christians, few of whom were literate, used X to sign documents as a token of their veracity.

This custom would also appear related to the modern use of X as a signature or in checkboxes, though we should never underestimate that this practice could just be because X is a distinctive and easy-to-form shape to make. Consider how we have X marks spots, dating to at least the early 1800s, which would seem to originate simply from, well, X marking spots.

Important documents were also sometimes signed with X and sealed with a kiss, and eventually the X-as-kiss emerged in letters and, now, text messages. The Oxford English Dictionary (OED) cites a letter by naturalist Gilbert White in 1763: “I am with many a xxxxxxx and many a Pater noster and Ave Maria, Gil. White.” Others think White’s X’s signified blessings, with an 1894 letter from Winston Churchill to his mother marking the earliest known use of the kiss X: “Please excuse bad writing as I am in an awful hurry. (Many kisses.) xxx WSC.”

The Algebraic X

X has been standing in for unknown mathematical quantities (variables) since the 17th century, a practice adopted from the French. The OED first cites it in English polymath (pun intended) Jonas Moore’s 1660 mathematical treatise, Arithmetic.

Why X? Contrary to a popular 2012 TED Talk, the OED offers:

The introduction of x, y, z as symbols of unknown quantities is due to Descartes (Géométrie, 1637), who, in order to provide symbols of unknowns corresponding to the symbols a, b, c of knowns, took the last letter of the alphabet, z, for the first unknown and proceeded backwards to y and x for the second and third respectively. There is no evidence in support of the hypothesis that x is derived ultimately from the mediæval transliteration xei of šay’ ‘thing’, used by the Arabs to denote the unknown quantity, or from the compendium for Latin res ‘thing’ or radix ‘root’ (resembling a loosely-written x), used by mediæval mathematicians.


The algebraic X is also responsible for the X in X-ray, a translation of the German X-strahlen (literally “X-beams”). German scientist Wilhelm Röntgen discovered them in 1895 and, taking a page from mathematics, so designated because he didn’t fully understand them.

The “unknown” X also produces that “indefinable quality” of the X-factor, which dates back all the way to the 1930s.

X’s sense of mystery probably led to X’s wide use in naming, from the X-Files to SpaceX, with X here conjuring up a sense of possibility, of wonder. Its associations with words like extreme and extra further lend it to so much branding (e.g., Xbox, Yukon XL, UberX). Names like Gas-X and Clean-X play with X as ex, or “former,” with X perhaps additionally calling up advanced technology, thanks to the letter’s “unknown” (read futuristic) resonances.

The unknown is also uncertain, which produces the X in Generation X, first used in the 1950s for a “generation of young people about whose future there is uncertainty.” Later uses of Generation X play upon valences of X as anxious or edgy for this supposedly disaffected post-Boomer population.

X is also a prominent sound in sex. Perhaps advertisers subliminally take advantage of this connection, but the XXX for pornographic content appears to come from the use of X for motion picture ratings for adult films. (I suspect the choice of X here prudishly alludes to the letter’s connotations with “wrong.”)

XXX, finally, was also used for the potency of various beers in the 19th century, likely leading to the trope of XXX for strong booze in cartoons.


Due to some upcoming wedding celebrations (I’m honored to be marrying my sister- and soon-to-be brother-in-law this weekend), Mashed Radish will taking Friday off.

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Element, O, P? The elements of “element”

Last post, I discussed how the four, newly confirmed elements are named. But what about the very word element? How did it get its name? Its etymology may not be so, er, elementary.

Building blocks and ABCs? It’s elementary. “Element.” Doodle by me.

The development of element

In English, the earliest record of element names the four elements: earth, air, water, and fire, which ancient and medieval philosophers believed made up the whole of the physical universe. The Oxford English Dictionary (OED) finds record of such usages as early as the 1300s.

The OED also finds, I should note, some early evidence of element that might refer to celestial bodies, suggesting that the word may have had multiple meanings even in its cradle.

We now know, of course, that the universe is composed of so much more than earth, air, water, and fire – and in a completely different manner. Though, if you stop to think about it, humans have discovered 118 elements, 24 of which are synthetic. That’s really not a whole lot of stuff making up the universe as we know it. And most of it actually just hydrogen.

Anyways, we might well say the the discovery of those four new elements – ununtrium, ununpentium, ununseptium, and ununoctium – owes a lot to those old theories, if we take the long view. And the four classical elements show their influence not only on the development of modern chemistry but also on Modern English, seen in the expressions in or out of (one’s) elements. See, each of the four elements was considered to be the natural realm for respective living beings. Think: birds in the air, fish in the sea. This usage, as the OED documents, dates back to the end of the 16th century.

Now, the OED first credits the modern chemical usage of element to Cornish scientist Humphry Davy (who also gets credit for the metallic suffix -ium, as we saw last post) in his lectures, Elements of Agricultural Chemistry, compiled in 1813. According to an 1815 edition of the work, Davy states:

By methods of analysis dependent on chemical and electrical instruments discovered in late times, it has been ascertained that all the varieties of material substances may be resolved into a comparatively small number of bodies, which, as they are not capable of being decompounded, are considered in the present state of chemical knowledge as elements. The bodies incapable of decomposition at present known are forty-seven.

I love that Davy’s lectures are called Elements of Agricultural Chemistry. And he even opens his lectures by observing that the “doctrines” of agricultural chemistry “have not yet been collected into any elementary treatises.” These examples aptly show that element and its derivative forms had already long been enjoying many senses outside of material contexts.

The ABCs of element 

OK, so what do we know about the etymological elements of element? The English word passes into English from the French element, which developed from Latin’s elementumLike English’s own element, this word could refer to a lot of things, including the notion of a “first principle.” As the OED describes it, Latin’s elementum is a “word of which the etymology and primary meaning are uncertain…”

This uncertainty has lead to a number of curious hypotheses. While noting its ultimately obscure origin, Eric Partridge wonders if elementum may have developed from *eligmentum, formed on “ēligere, to choose (the fundamental substance or basic principle) from (a welter of physical phenomenon).”

Meanwhile, Earnest Klein, also noting the obscure origin, suggests one proposal, *elepantum, is “most probable.” This *elepantum, so it’s argued, meant “ivory letter,” loaned from the Greek ἐλέϕας – “elephant” or “ivory,” and source of elephant – but altered by some Etruscan influence.

Ivory letters? Surely Klein means letters carved into (or possibly from?) ivory. The ivory component of this argument may be lacking tusks, but the letter part is important.

For Latin’s elementum could also refer to that building block of reading and writing: a “letter,” as in a letter of the alphabet. English features the metaphor, too. We don’t just learn our ABCs in elementary school. We also learn the ABCs of computer programming or basketball, say.

Scholars are also certain that Latin’s elementum is actually a translation of the Greek στοιχεῖον (stokheion), a word with equally many meanings.

For this word, I consulted Liddell and Scott’s Greek dictionary, and they gloss it as “one of row,” referring to, in the singular, “the shadow of the gnomon (of a sundial)” as well as “a letter.” In the plural, the word referred to the classical “elements” (a usage to attributed Plato) as well “rudiments” in the more general sense. At root is στοῖχος (stoikhos), a “row” or “rank,” source of English’s stoichiometry, speaking of chemistry.

But why the form elementum for that Greek  stokheionCarefully sound out the first three syllables of the word. Does it sound like letters lm, and n?  Was elementum a way of referring to the Roman alphabet via its second half, viz. alphabet (from Greek, referring to its first two letters, alpha and beta) or abecedarium (from post-classical Latin, joining a later Roman alphabet’s first three)?

But, then again, why the second half? Seems a bit fanciful, no?

Well, esteemed etymologist Anatoly Liberman thinks there may just be something to this, including the fancy. Through a series of sound changes beyond our element here, Liberman makes the case that elementum is an alteration of alimenta, “food” or “sustenance,” with each letter in the alphabetic sequence “nourishing” the next. (For  alimenta, think English’s alimentary). The resulting elementum additionally punned on lm, and n. And all as a sort of act of fancy on the part of some scholar. As Liberman puts it:

To put it differently, elementum was not derived from an identifiable root with the help of a suffix but coined whole to gloss Greek stoikheon…Some grammarian must have taken alimenta ~ *olimenta and changed it into elementa (the singular elementum postdates the plural).

This means Latin was first using elementa to refer to “letters,” later figuring other “rudiments” or “first principles” with the term  and then back-forming the singular, elementum.

Further efforts have attempted to link elementum to Semitic roots, including the ancient Canaanite alphabet, but these theories are certainly not easy as ABC.

Whether or not element ultimately imitates the recitation of any letters is up for debate, but one thing is for sure: its Latin and Greek references to the ABCs proves element is pretty elementary, in a manner of speaking, after all.

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