Latin stopped being anyone’s native language over a thousand years ago, yet somewhere in a Vatican dictionary is a word for “helicopter” — helicopterum. At first glance, this seems like an anachronism. Helicopters weren’t even invented until the 20th century, many centuries after Latin fell out of regular use. So how did a language associated with togas and gladiators end up with a term for a modern rotor-powered aircraft? The answer lies in one of the more unusual side projects of the Catholic Church: the ongoing effort to keep Latin functioning as a living language.

It’s been centuries since any country spoke Latin as an everyday language, but it never actually disappeared. While Latin began to die out in the sixth century, not long after the fall of Rome in 476 CE, it remained the working language of scholarship, law, and science well into the early modern period, and it’s still the official language of the Vatican and the Catholic Church. Indeed, papal documents, church law, and official Vatican communications are drafted in Latin even now. (Italian serves as the everyday working language of the Vatican.)

Today, Latin is considered a dormant language rather than an extinct language. An extinct language is entirely gone and no longer written, with no living speakers and no active cultural usage. Extinction is the complete and final end of a language’s existence. A dormant or dead language, on the other hand, offers some hope. Dormant languages such as Latin survive in written form, they are taught and learned, and people still speak them. They may be called dead, but that’s something of a misnomer — in some cases, including Latin, these languages are very much alive. 

The fact that Latin is still taught and studied — and, albeit quite rarely, spoken — created a practical problem. How do you write about airplanes, telephones, the internet, or space travel in a language that predates all of them? The Vatican came up with a solution. 

Starting in 1992, a team of Vatican scholars under the Latinitas Foundation began publishing the Lexicon Recentis Latinitatis, a dictionary specifically designed to fill in these gaps. The reference work translates both English and Italian terms, building them out of existing Latin roots, prefixes, and suffixes, the same way the Romans themselves once expanded their own vocabulary. The project has grown to include roughly 18,000 entries across 450 pages, covering everything from lampshades (umbráculum lámpadis) to computers (instrumentum computatórium). 

Coining a Latin word for “helicopter” was perhaps easier than some others, because it was already based on words from classical antiquity. The word was created in 1861 by a French inventor using two Greek roots: helix, meaning “spiral” or “coil,” and pteron, meaning “wing” (the same pteron found in “pterodactyl,” or “winged finger”). 

Since Latin freely absorbed Greek vocabulary throughout its history, adapting those same roots into a Latin noun was a natural fit, producing helicopterum. The coinage and its potential usage weren’t just theoretical, either. The Vatican scholars tasked with creating the Lexicon Recentis Latinitatis may well have felt a degree of satisfaction knowing that the Vatican City Heliport could finally be referred to using a Latin term that combined new translations for two modern words: aëriportus helicopterorum.

The Latinization of “helicopter” is far from an isolated case. The same Vatican dictionary includes Latin coinages for all manner of modern actions, events, and inventions, from jogging (cursus pedester) to fog lights (pharus adversus nebulam) and traffic jams (fluxus interclusio). In most cases, these words were built using the same method of combining classical roots to form new compounds. 

Together, they reflect the broader philosophy bound up in the Lexicon Recentis Latinitatis. Rather than letting Latin become a purely historical language, confined to inscriptions and old manuscripts, its custodians have chosen to help it adapt and evolve to depict the modern world, one carefully constructed word at a time.

Despite the pains of flight delays, ever-shrinking seats, and exorbitant baggage fees, travel is typically easier today than it was centuries ago. Just look at people back in the Middle Ages: They had no way to book an inn on the internet, nor could they rent a horse in advance like you would reserve a rental car today. And forget about flying — cross-country or international journeys were long, arduous endeavors that took weeks or even months, rather than the mere hours we spend on planes now. These difficulties are why the word “travel” was coined in the first place.

“Travel” is derived from the word “travail,” referring to a laborious task that requires extra effort and takes a toll on the body and brain. The roots of “travail” reveal even more pain: It comes from the Old French word of an identical spelling meaning “to toil,” which comes from the Vulgar Latin tripaliare, meaning “to torture.” “Travail” entered the English lexicon during the mid-13th century, and by the late 13th century, it was widely used to describe the challenges women experienced during childbirth. However, that specific usage is now obsolete.

Back to the idea of traveling: For centuries, travel was viewed as an onerous task. It took an excessive amount of time to move from one place to another, there were uncomfortable accommodations along the way, and journeyers were vulnerable to crime. Given these common hardships, it was natural for people to refer to travel (though it wasn’t yet called that) as a travail.

Around the year 1300, the Middle English verb travailen appeared, meaning “to make a journey.” This gave rise to the word trauel (also sometimes spelled as trawaile, travell, travale, trauaille, etc.) in the late 14th century. It was only when Modern English began to take shape around the year 1600 that “travel” became the standard spelling. Today, travel does still involve some travail, but on a much different scale.

Many of our holidays are unrelated to religion. Think of Independence Day, Labor Day, Memorial Day, Thanksgiving, and notable days such as Flag Day, Arbor Day, Presidents Day, and Martin Luther King Jr. Day. Each of those honors a historical event, a notable person or group of people, or a secular activity. But a lot of other American holidays are tied specifically to the Christian religion. Hidden inside the word “holiday” is a clue to the religious connotations of these days of celebration.

“Holiday” derives from the Old English haligdaeg, meaning “a day consecrated to religious observance,” which included the Sabbath. The first syllable, halig, means “holy,” and the second, daeg, means “day.”

Christmas, celebrated widely in the United States by both Christians and people who don’t follow the religion, carries the religious sense of “holiday” in its name. It comes from the Old English Cristes maesse, with the second half from the Latin messa, referring to a Christian service. 

In Britain, there are a few more traditionally celebrated religious holidays with the massa origin. Candlemas, celebrated 40 days after Christmas on February 2, marks the end of the extended Christmas cycle. Several holidays tied to the agricultural calendar are recognized in the church in Britain: Lammas (August 1) includes a church blessing for the harvest of the first grain, Michaelmas (September 29, or November 8 in Eastern Christian religions) marks the end of the agricultural year, and Martinmas (November 11), also called St. Martin’s Day, signals the end of the harvest season and the slaughtering of livestock.

In the 14th century, “holiday” entered English, referring to a religious festival, which also meant it was a day off work for laborers. Those two senses diverged in the 16th century, and slowly the word “holiday” came to refer to any days that provided a respite from work, with or without a religious element. Over time, that second usage was extended to refer to any occasion of joy and gaiety. A holiday can be celebrated at any time — it can be official or created for a specific purpose, such as Talk Like a Pirate Day (September 19) or National Mac and Cheese Day (July 14). In British English, “holiday” is now synonymous with “vacation.”

In medieval illuminated manuscripts, significant dates were highlighted in red. Then the widely used Book of Common Prayer, published in 1549, included a calendar showing the holy days in red. Each red-letter day was originally a feast day or a celebration of a saint, but that term, too, has lost its religious significance.

Now the idiom “red-letter day” refers to any happy, special, memorable, or important day, with no recognition of saints. Graduating from college, closing on a house, starting a new business, and celebrating a milestone birthday might all be called red-letter days.

Every word in the English language is made up of some combination of the 26 letters of the alphabet. However, the alphabet has undergone some changes since its inception sometime around 600 BCE. The letter “j” wasn’t added as the final letter until the 17th century, and one letter is notable for its absence in the modern alphabet: thorn (þ). This character, which once held a prominent place in Old English writing, survives today in a curious way, its ghostly presence in the most frequently used word in the English language: “the.”

Thorn — written as “þ” in its lowercase form and “Þ” when capitalized — represented the “th” sound (as in “thin” or “they”) in Old English. It originated from the runic alphabets used by early Germanic peoples, specifically the Elder Futhark rune ᚦ (Thurisaz). Old English, spoken and written in England up to approximately 1150 CE, employed thorn extensively. Even when Old English was written using the Latin alphabet, scribes continued using thorn because Latin lacked dedicated symbols for the “th” sounds common in Germanic languages. 

Many words we now recognize instantly once appeared with thorn at the front. The definite article “the,” for instance, was commonly written as “þe.” “Thou” was spelled “þū” and “thee” as “þē.” Thorn featured all across the Old English vocabulary — in “three,” “thing,” “think,” and countless other words — as a practical way to represent native phonetics.

Thorn worked perfectly well as a letter until the beginning of the Middle English period and the Norman Conquest of England in 1066. When William the Conqueror took the English throne, scribes trained in France came to England, replacing their English counterparts in many positions of power and influence. These Norman scribes did not use thorn — instead, they preferred the “th” spelling they were familiar with from Old French.

Over the following centuries, “th” gradually replaced thorn in many documents, especially in official or formal writing. But thorn did not disappear immediately — it remained common in handwriting throughout much of the Middle English period and well into the 1400s. In Scotland, thorn managed to survive even longer, appearing — albeit rarely — in handwritten documents as late as the 18th century. 

The death knell for thorn came with the arrival of the printing press in England. In 1476, William Caxton, an English merchant and translator, established the country’s first printing press in London. Because the first printing presses came from continental Europe, they featured characters for the printing of Latin and other European languages, such as German and French. Thorn was not among them. 

By this stage, despite “th” being well established, thorn was still in use, but primarily for only the most common words such as “þe” (“the”). Early English printers weren’t willing to do away with thorn completely, so they used the letter “y” to represent “þ.” It was a logical choice, as in some medieval scripts the thorn looked quite similar to “y,” especially in handwritten form, making it an easily understood substitute.

Interestingly, it was this substitution that gave rise to the famous — and frequently misunderstood — “Ye Olde” construction often used in the names of pubs, cafes, and shops in England, and mimicked around the English-speaking world (for example, Ye Olde Curiosity Shop in Seattle and Ye Olde College Inn in New Orleans). When you see a business called “Ye Olde Tea Shoppe” or “Ye Olde Dog and Duck Tavern,” the “ye” should be pronounced not with a “y” sound but as “the” — it is, after all, a typographical fossil that comes from thorn.

Despite the early use of “y” in English printing presses, the digraph “th” (two letters working together) remained dominant. Eventually “th” fully replaced thorn (as well as its substitute “y”) in printed English, aligning English orthography (spelling) more closely with French and Latin while simplifying and standardizing the printing procedure. 

Today, thorn no longer exists in English — but it hasn’t vanished entirely. Thanks to its Old Norse origins and the highly conservative nature of the Icelandic language, thorn is still used in Iceland. And, in a sense, the letter thorn still lingers in everyday English — albeit only phonetically — in our most common word, “the.”