10 longest words in the dictionary and how to pronounce them to seriously impress your kids (and they'll love to have a go too)

These are the top 10 longest words in the dictionary and it's not just Supercalifragilisticexpialidocious

child speaking with speech bubble written on wall, words Supercalifragilisticexpialidocious written inside bubble
(Image credit: Getty Images)

The 10 longest words in the dictionary have been revealed, as well as how to pronounce them - if you're a fan of busting out Supercalifragilisticexpialidocious at every opportunity then you can seriously impress your kids with these.

If you're looking for things to do with the kids at the weekend that don't cost a lot, or that will capture their attention when they come home from school and you're running out of fun facts for kids, then you might want to put their reading skills to the ultimate test. But this is no ordinary test - see how many of the 10 longest words they can pronounce or spell (and if you really want to impress them make sure you master it first).

The English language constantly evolves, with more than 700 new words, phrases and senses being added in the latest Oxford English Dictionary (OED) update. From TikTok slang to the downright bizarre, you’d be surprised to know about the sorts of words that even have a place in the dictionary. 

Placing the focus on the bizarre, the language experts at Preply have revealed what the longest words in the dictionary are, as well as what they mean and how to pronounce them. And we think your kids will be obsessed...

1. Pneumonoultramicroscopicsilicovolcanoconiosis

Taking the crown for the longest word in standard dictionaries is pneumonoultramicroscopicsilicovolcanoconiosis. It is made up of a staggering 45 letters, this word refers to a lung disease triggered by breathing in very fine silicate or quartz dust. 

Here's how to pronounce it


2. Hippopotomonstrosesquippedaliophobia

Being the second longest word in the dictionary, it is ironic that hippopotomonstrosesquippedaliophobia is the name for a fear of long words. Yes. You couldn't make it up. Unfortunately learning how this 36-letter word is spelt won't help in a game of Scrabble as there is a maximum of seven tiles per play.

Here's how to pronounce it


3. Supercalifragilisticexpialidocious

A term coined by our favourite British nanny Mary Poppins, supercalifragilisticexpialidocious refers to something extraordinarily good or wonderful. surprisingly it's only got 34 letters, meaning it's been pushed to third place. But if you or your kids struggle sounding it out, there's always the song that will help. However, we can't promise you'll get it out of your head before you get to the end of this article.

Here's how to pronounce it


Dick Van Dyke as Bert, Julie Andrews as Mary Poppins, Karen Dotrice as Jane Banks and Matthew Garber (1956 - 1977) as Michael Banks in the Disney musical 'Mary Poppins',

(Image credit: Getty Images)

4. Pseudopseudohypoparathyroidism

In the medical world, pseudopseudohypoparathyroidism is an inherited condition that causes short stature, round face, and short hand bones. But let's hope that not many doctors have to write it out in full as remembering the order of the 30 letters will be a struggle - let alone fitting it onto a medical record. We wouldn't like to be the ones to have to write that on one of those spa day pre-treatment forms!

Here's how to pronounce it



5. Floccinaucinihilipilification

Floccinaucinihilipilification refers to the act or habit of categorising something as having no value or being worthless. Despite its meaning, the word has an ample 29 letters and is generally used in a humorous context. And if you're looking for an ultimate comeback in an argument then you might want to practice this one and we're sure you'll leave them speechless.

Here's how to pronounce it


6. Antidisestablishmentarianism

History enthusiasts may already know this, but antidisestablishmentarianism refers to a political movement in 19th-century Britain that was determined to separate the Church and the state. Despite being 28 letters long, it's one of the easier ones to remember.

Here's how to pronounce it


7. Honorificabilitudinitatibus

Derived from Medieval Latin, honorificabilitudinitatibus refers to the “state of being able to achieve honours” and if you really want to impress your kids at university, why not stump them by writing the 27-letter word inside their graduation card? 

Here's how to pronounce it


8. Thyroparathyroidectomized

Thyroparathyroidectomized refers to the surgical removal of the thyroid and parathyroid glands. Thankfully the official name is not used that very often as even we'd struggle with writing the 23-letter word down on our work absence record.

Here's how to pronounce it


9. Dichlorodifluoromethane

What do you call a colourless nonflammable gas that is liquefied by pressure? Dichlorodifluoromethane. But this 23-letter word isn't one to repeat after too many alcoholic drinks or you could end up coming out with a different word - and one that you don't want your kids repeating.

Here's how to pronounce it

“Dahy-klawr-oh-dahy-floo r-oh-meth-eyn”

10. Incomprehensibilities

Finally moving on to the more pronounceable words, incomprehensibilities - this 21-letter word refers to the state of being impossible or very difficult to understand.  

Here's how to pronounce it

“In-compre-hen-sibil-ities “ 

In other news, Is your child not playing with their toys? 3 reasons why and what to do about it and Rishi Sunak launches crackdown on ALL parents to cut the number of kids holidaying during term time, but families believe the issue ‘isn’t the parents’

Selina Maycock
Senior Family Writer

Selina is a Senior Family Writer for GoodtoKnow and has more than 16 years years of experience. She specialises in royal family news, including the latest activities of Prince George, Charlotte, Louis, Archie and Lilibet. She also covers the latest government, health and charity advice for families. Selina graduated from the University of Sheffield in 2006 with a degree in Journalism, and gained her NCTJ and NCE qualifications. During her career, she’s also written for Woman, Woman's Own, Woman&Home, and Woman's Weekly as well as Heat magazine, Bang Showbiz - and the Scunthorpe Telegraph. When she's not covering family news, you can find her exploring new countryside walking routes, catching up with friends over good food, or making memories (including award-winning scarecrows!)