The longest word documented in major unabridged English dictionaries is pneumonoultramicroscopicsilicovolcanoconiosis. It is a 45-letter word, which means a lung disease caused by inhalation of very fine silica dust or quartz dust. According to Dictionary, the funny thing is that most of these words were made up by doctors, scientists, and researchers. Because they needed very specific terms for very specific things.
And the rest of the words were created by somebody who simply woke up one morning and decided English was way too simple. Read this article to learn about the 21 longest words in English and their meanings, along with how to pronounce them.
- The longest dictionary-recognised English word contains 45 letters.
- Some of the longest words are derived from the medical and scientific fields.
- One word became famous due to the fictional book character Mary Poppins.
- Few words are long, but they have basic meanings.
- One long word means the fear of long words.
Why are Some English Words So Ridiculously Long?
Blame science. Whenever scientists find a new thing, they have to name it. They don’t pick something short and easy. They often combine Greek and Latin words to name the invention. Doctors do the same thing. Before long, you end up with words that look like they were made when someone fell asleep on a keyboard. Not only science or doctors get credit for this. Some words come out of literature and politics. You may be surprised to know that few of them got famous because people thought that it was a fake word.
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21 Longest Words in English and Their Meanings
1. Pneumonoultramicroscopicsilicovolcanoconiosis
This 45-letter word is the longest word in major English dictionaries. In Wikipedia, it means a lung disease caused by inhaling very fine silica or quartz dust.
How to pronounce it: New-muh-noh-ul-tra-my-kroh-skop-ik-sil-i-koh-vol-kay-noh-koh-nee-oh-sis
Fun fact: According to Study International, the disease itself is real, but this long name was reportedly coined in the 1930s by a word enthusiast who wanted to create a deliberately long word.
2. Hippopotomonstrosesquippedaliophobia
This word deserves an Oscar award for irony. It means the fear of long words. It has 36 letters in it. Just imagine you tell someone you suffer from hippopotomonstrosesquippedaliophobia and watch their reaction.
Pronunciation: hip-oh-pot-oh-mon-stroh-ses-kwip-ed-ay-lee-oh-foh-bee-uh
3. Supercalifragilisticexpialidocious
There was a popular fictional character in a book and her name was Mary Poppins. She was a part of a 1964 film and this word was used in that film. It has 34 letters and means something wonderful, brilliant, or extraordinary.
Pronunciation: soo-per-cal-uh-frag-il-is-tik-ek-spee-al-ih-doh-shus
4. Pseudopseudohypoparathyroidism
It is a rare inherited condition that shares characteristics with another disorder called pseudohypoparathyroidism, which explains why “pseudo” appears twice. The word is 30 letters long.
Pronunciation: soo-doh-soo-doh-hy-poh-par-uh-thy-roy-diz-um
5. Eellogofusciouhipoppokunurious
It is an American slang word that means “very good” or “very fine”. Thirty letters for a phrase most people would replace with “excellent”.
Pronunciation: ee-loh-goh-fus-see-oh-hip-oh-poh-kyoo-noor-ee-us
6. Floccinaucinihilipilification
It means deciding that something is worthless or not worth paying attention to. This word has 29 letters.
Pronunciation: flok-see-naw-see-nih-hil-ih-pil-ih-fi-kay-shun
7. Antidisestablishmentarianism
This is a word that everyone tries hard to memorise. It refers to opposition to separating an established church from the state. This word was first used in 19th-century Britain during debates surrounding the Church of England. It has 28 letters.
Pronunciation: an-tee-dis-es-tab-lish-men-tair-ee-an-iz-um
8. Spectrophotofluorometrically
A scientific term used to measure fluorescent light. Unless you’re working in a laboratory, you’ll probably never need to say it. It contains 28 letters.
Pronunciation: spek-troh-foh-toh-floor-oh-met-rik-lee
9. Honorificabilitudinitatibus
Shakespeare fans might recognise this one. It appeared in Love’s Labour’s Lost and means “the state of being able to achieve honours”. It has 27 letters.
Pronunciation: on-or-if-ik-uh-bil-ih-too-din-ih-tat-ih-bus
10. Psychoneuroendocrinological
This word is related to psychology, neurology, and endocrinology. According to Quillbot, it means how the brain, behaviour, and hormones interact. It has 27 letters.
Pronunciation: sy-koh-noor-oh-en-doh-krin-oh-loj-ik-ul
11. Electroencephalographically
A word linked to monitoring and recording electrical activity in the brain. The word has 27 letters.
Pronunciation: ee-lek-troh-en-sef-uh-loh-graf-ik-lee
12. Radioimmunoelectrophoresis
A laboratory technique used to identify and measure substances such as proteins. The word has 26 letters.
Pronunciation: ray-dee-oh-im-yuh-noh-uh-leck-truh-fuh-REE-suhss
13. Thyroparathyroidectomised
It is a medical term describing someone who has had both the thyroid and parathyroid glands removed. It has 25 letters.
Pronunciation: THIGH-roh-par-uh-THIGH-royd-ECK-tuh-myzd
14. Laryngotracheobronchitis
Doctors know this one. It means inflammation of the larynx, trachea, and bronchi. It has 24 letters.
Pronunciation: luh-ring-goh-tray-kee-oh-bronk-eye-tis
15. Microspectrophotometries
A technical method used to analyse tiny samples by measuring light. It has 24 letters in it.
Pronunciation: my-kroh-spek-troh-foh-tom-uh-treez
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16. Dichlorodifluoromethane
It is a chemical that was once used in refrigeration systems and aerosol products. It’s also known as Freon. It has 23 letters.
Pronunciation: dye-klor-oh-dye-floor-oh-meth-ayn
17. Subcompartmentalisation
It simply means dividing something into smaller sections. It has 23 letters.
Pronunciation: sub-kom-part-men-tal-eye-zay-shun
18. Counterrevolutionaries
People who oppose a revolution or seek to reverse it. It has 22 letters.
Pronunciation: kown-ter-rev-uh-loo-shun-air-eez
19. Xenotransplantation
A medical procedure involving the transplantation of organs or tissues from one species to another. It has 19 letters.
Pronunciation: zee-noh-trans-plan-tay-shun
20. Incomprehensibilities
It means the things that are difficult or impossible to understand. It has 21 letters.
Pronunciation: in-kom-preh-hen-sih-bil-ih-teez
21. Sesquipedalianism
This word refers to the habit of using excessively long words. It has 17 letters.
Pronunciation: ses-kwih-pih-day-lee-uh-niz-um
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The Longest Word Ever Created
Believe it or not, none of the words above holds the all-time record. That title belongs to the full chemical name of titin, the largest known protein in the human body. According to Your Dictionary, it has 189,819 letters. Pronouncing the whole thing would take several hours. That’s one reason dictionaries wisely leave it out.
Sources and References:
- Dictionary – Most long words are made by scientists, doctors, and researchers.
- Study International – Pneumonoultramicroscopicsilicovolcanoconiosis is the name of a lung disease.
- Quillbot – The word ‘psychoneuroendocrinological’ is related to psychology, neurology, and endocrinology.
- Your Dictionary – The longest word ever created has 189,819 letters.
