Scrabble players may be well familiar with the very rare cluster of vowel-only words that exist, but if you’ve ever gotten into a mid-game spat as to what exactly aa, ae, ai, oe, and eau mean, now’s your chance to finally defend these unique, pint-sized words. Who knows, you may even find a way to drop one into a sentence to really dazzle (or confuse) your friends.
First, let’s talk definitions.
Aa is a geological term referring to basaltic lava that forms rough, jagged masses with a light, frothy texture. It comes from Hawaii – land of the volcano – where it is pronounced ‘a-‘a.
Ae comes from the opposite side of the globe, care of Scotland, where it refers to the number one.
Ai is commonly affiliated with the modern-day acronym for Artificial Intelligence, but in actuality, it’s just another name for our favorite slow-moving animal, the maned sloth. And believe it or not, it’s actually got two syllables, pronounced as eh-eye.
Oe is yet another word derived from the brevity-loving Scots, meaning grandchild.
Eau also brings some international flair as one of many French words we’ve adopted into English. Eau – commonly l’eau – means water in French, but in English, eau typically means a watery solution, such as perfume or liquor.
Why do we have these words?
Compared to other languages around the world, English has very few vowel-only words (although for the record, a and I, two of the shortest words around, also count!) Of the ones that do exist, they’re rarely used.
The reason for their rarity comes down to the origin. English is well-known for its adoption and evolution of words from languages all around the world. All of the five short, vowel-only words above derive from somewhat archaic sources, or are specialty words that are generally unique to the culture that crafted them. We don’t encounter maned sloths in our daily lives – but Portuguese-speaking Brazilians, from whom the word was derived – may be more familiar with the creature and its unique name.
Same goes for Oe. English-speaking Scots likely brought the word to the wider stream of the English language, but with the advent of globalization, more and more grandkids are called just that instead of this traditional term.
On the flip side, it’s worth noting that English words without vowels are even more rare and carry equally bizarre definitions. Tsk tsk, nth (as in nth degree) and psst are a few better-known examples. Psst is actually similar to a number of other onomatopoeia expressions that are without vowels, such as brr, hmm, or shh. But fair warning, Scrabble champs – you might not find those words in the OED, aka the logophiles’ gospel.