Stock up on short words

"Cwm" is not a typo: Three-letter words you didn't know existed

Need a few tricks up your sleeve for playing Scrabble? It’s not always the long words that will impress the other players: Sometimes it’s the surprisingly short combination of letters that none of them knew. Have you ever heard of unassuming three-letter words like "cwm" or "zax"? Those aren’t typos! Let’s explore some of the most obscure –yet perfectly valid– three-letter words.

Before you ask: it’s pronounced "koom". If you run out of vowels in your Scrabble set, this might save you. It refers to a deep, steep-walled valley, often carved by glaciers.

The term comes from Welsh, where it simply means "valley." Many places in Wales proudly bear the name, such as Cwmbran, a town in South Wales, or Cwmtwrch, a village with a name that translates to "Valley of the Wild Boar."

A "zax" is a tool used for cutting or trimming roof slates with precision. The word shares linguistic roots with seax, an Old English word for a short sword or knife.

Plus, in Scrabble, the mighty "Z" (10 points!) paired with "A" (1 point) and "X" (8 points) makes this one of the highest-scoring three-letter words you can play!

No, it’s not a mythical sea creature. "Voe" refers to a small bay or narrow creek that extends inland from the sea. These sheltered inlets are particularly found in Scotland, where they provided safe harbor for fishermen and sailors for centuries.

Some of these sailors were Vikings who once ruled the territory, and who called these bays with the Old Norse word vágr (bay or inlet.)

If you ever see a rowdy, loudmouthed troublemaker being kicked out of a bar in Britain, you might hear someone call them a "yob."

Here’s the funny part: There’s no Old English etymology involved. It’s just "boy" spelled backwards (a bit of Cockney slang trickery).

A very specific noun, but a valid one. A "pyx" is the container used in churches to hold consecrated bread.

The term comes from Latin pyxis, meaning "small box," which in turn derives from the Greek pyxos, a type of boxwood tree. Those three letters combined would earn you at least 15 points!

Have you ever seen the interior of a rock lined with dazzling, beautiful crystals? You might have been looking at a vug.

It’s a small cavity inside a rock that often exposes these pockets of hidden treasures, like quartz, amethyst, or more exotic gems. The word vug comes from the Cornish language, where vooga meant "cave" or "hollow."

Sure, playing "OK" is useful, but have you tried "Oka"? It’s a type of cheese from Canada, and also a historical unit of weight used in Turkey.

The cheese is named after the village of Oka in Quebec, where Trappist monks started making it in the late 19th century.

Gox might sound like the name of some sci-fi character. But it’s just a short abbreviation to refer to "gaseous oxygen."

"O₂" is the more common way to represent it, but "gox" is sometimes used by those in scientific and industrial contexts.

To be fair, you could pluralize any two-letter word by adding an S. "Xis" (the plural of the 14th Greek letter Ξ ξ) is no exception.

Just so you know, "xi" is not the translation of our "X," as you might think. What we call an "X," the Greek would call a "chi."

"Ait" is mostly used in Britain to describe little landmasses that pop up in waterways, like those dotting the Thames.

The word (sometimes spelled eyot) comes from Old English iegoth, meaning "small island." Though it’s not common in everyday speech, you’ll still find it in place names and historical writings.

Before they fully mature, newts crawl on land: this is when we call them efts. These tiny, bright-colored amphibians can be found around damp forests, looking like pocket-sized dragons.

The word eft has been around for centuries, coming from Old English efeta, which evolved to ewt, and ultimately to newt.

The gnu (pronounced "new" or "guh-noo") is better known as the wildebeest, that sturdy African antelope famous for its dramatic migrations across the Serengeti.

The word gnu comes from the Khoisan languages of southern Africa and was first recorded by European explorers in the 18th century. The alternative name wildebeest is the Dutch word for "wild beast," of course.

"Nix" means to reject, cancel, or put an end to something. The word comes from the German nichts, meaning "nothing."

It entered American English in the 19th century, likely through German immigrants. Over time, it became a snappy, no-nonsense way to say "no."

An "ulu" is a traditional Inuit knife with a characteristic curved blade, perfect for chopping, skinning, or even cutting a child's hair (yes, really).

The name comes from the Inuktitut word ᐅᓗ (ulu), which roughly translates to "woman’s knife"

because it was traditionally used by Inuit women for household and hunting tasks.

Mind games

The scruffy barber and the swift tortoise—does reality even make sense?

Image: 愚木混株 cdd20

Some ideas challenge what we think we know—paradoxes twist logic until reason bends or breaks. These classic thought experiments, from ancient puzzles to modern contradictions, expose gaps in philosophy, math, time, and perception. Here are 10 paradoxes that’ll warp your mind and leave you questioning reality.

Image: Josh Sorenson

If a barber shaves everyone who does not shave themselves, who shaves the barber? If he shaves himself, he must not; if he doesn’t, he must.

This self-referential paradox, posed by Bertrand Russell in 1918, demonstrates a fundamental problem in set theory. It inspired Russell's theory of types, which aimed to avoid such contradictions in formal logic and mathematics. Perhaps the barber will simply choose to grow a beard.

Image: Joshua Hoehne

The statement "This sentence is false" cannot be true or false. If true, then it’s false; if false, then it’s true.

Known since ancient Greece as the Epimenides paradox, it underpins challenges in many logical systems. Although it seems simple at first, deeper thought reveals there is no resolution. Many have tried to solve or circumvent it, yet it remains unsolved.

Image: Zoltan Tasi

If you replace every part of a ship, is it still the same ship? What if you reassemble the old parts into a second ship?

This metaphysical problem dates back to Plutarch. It challenges identity and continuity, and has many analogs in biology (e.g., human cells constantly replacing themselves) and even AI (replicated minds in machines).

Image: Luca Ambrosi

Achilles and a tortoise race each other. As a courtesy, Achilles gives the tortoise a head start. However, Zeno argues Achilles can never catch it, because he must first reach where the tortoise was before, infinitely.

Although this paradox seems crazy and absurd—in real life, obviously Achilles would win the race—what Zeno is pointing to are the infinite gaps between finite numbers. The absurd argument, being that all motion is impossible due to infinite division, helps illustrate the limits of mathematical models of the world.

Image: Gianluca Carenza

If you went back in time and killed your grandfather before your parent was born, how could you exist to do it in the first place?

This classic time travel paradox highlights the problems with causal loops. Theoretical physics offers some resolutions, such as branching timelines (as in the "many-worlds interpretation") or even stranger concepts like "closed time-like curves"—but its true resolution is still debated today.

Image: Caryn Sandoval

The unexpected hanging paradox involves a judge sentencing a prisoner to be hanged on an unknown day of the following week, but the execution must be a surprise. The prisoner logically deduces he cannot be hanged on the last day, nor the day before, and so on, concluding he will not be hanged at all. The next week, to the prisoner’s surprise, the executioner knocks on the prisoner's door at noon on Wednesday.

The unexpected hanging paradox, also known as the surprise test paradox, concerns a person’s expectations about the timing of a future event they are told will occur unexpectedly. It poses a problem in epistemic logic—our knowledge about what we know—and has no widely accepted resolution.

Image: Max Muselmann

A time traveler brings a copy of Shakespeare’s Hamlet to the past before Shakespeare wrote it. Who actually authored it?

This paradox suggests that time travel allows the emergence of information or objects with no discernible origin. It is a common trope in science fiction and defies causality, sparking heated debates in temporal logic.

Image: Maximus Meadowcroft

Can an all-powerful being create a stone so heavy that it cannot lift it?

This simple question highlights one of the main paradoxes behind the concept of omnipotence. Some resolve it by limiting omnipotence to what is logically possible; others reframe omnipotence as maximal power rather than the ability to create contradictions.

Image: Sarah Doffman

Removing one grain of sand doesn’t make a heap cease to be a heap. So, when does it stop being a heap?

This problem highlights the issue of vague definitions. At its core, it challenges not logic itself, but our use of language and the way we categorize concepts.

Image: Point3D Commercial Imaging Ltd.

A hotel with infinite rooms is full, but can still accommodate new guests by shifting each one to the next room.

This paradox, created by David Hilbert, illustrates the strange properties of infinite sets—whether rooms or any infinite collection of objects. It is used in set theory to demonstrate how infinities can behave in non-intuitive ways.