The Oxford English Dictionary contains over 170,000 words in current use, but what are the longest words in the English language?
The longest word in English is the chemical name for the titin protein found in humans. It is named after the chemicals which make it up and has 189,819 letters. This would fill pages of this article alone, although it has even been disputed if it forms a real word at all! For this reason, and because dictionaries tend to omit technical names of chemicals, you won’t find it written in this list.
Anyway, before we get side-tracked, we’re here to focus on the longest English words in the dictionary. So, let’s get into it! Here is a list of 11 of the longest words in English:
The 11 longest English words
1. Pneumonoultramicroscopicsilicovolcanoconiosis (45 letters)
The longest English word in the dictionary is Pneumonoultramicroscopicsilicovolcanoconiosis, which is a lung disease caused by the inhalation of very fine silicate or quartz dust.
How is the longest word in the English language pronounced? Press play find out!
2. Hippopotomonstrosesquippedaliophobia (36 letters)
The second longest word on our list is Hippopotomonstrosesquippedaliophobia. Hippopotomonstrosesquippedaliophobia is the name for the fear of long words, how ironic!
3. Supercalifragilisticexpialidocious (34 letters)
Are you a Mary Poppins fan? A fabulously nonsensical word derived from the popular film Mary Poppins, Supercalifragilisticexpialidocious mean something which is great or extraordinary. It’s…
4. Pseudopseudohypoparathyroidism (30 letters)
Pseudohypoparathyroidism is a genetic disorder associated with resistance to the parathyroid hormone. It is characterized by short stature, a round face, short neck, and shortened bones in the hands and feet.
5. Floccinaucinihilipilification (29 letters)
Floccinaucinihilipilification is the action or habit of describing or estimating something as unimportant or worthless. Easy for you to say…
6. Antidisestablishmentarianism (28 letters)
One that I learnt in history class! Antidisestablishmentarianism describes a political movement in 19th century England against the disestablishment or removal of the Church of England as the official state church of England, Ireland and Wales. You can still use it today to refer to opposition to the withdrawal of government funding or support for a particular church or religion.
7. Honorificabilitudinitatibus (27 letters)
From the works of Shakespeare, the meaning of honorificabilitudinitatibus is the state of being able to achieve honors.
8. Thyroparathyroidectomized (25 letters)
A medical term for the surgical removal of both the thyroid and parathyroid glands.
9. Dichlorodifluoromethane (23 letters)
Dichlorodifluoromethane is a colorless gas and cooling or freezing agent for consumer use, sold under the name Feon-12. The technical definition of dichlorodifluoromethane is a chlorofluoromethane CCl2F2.
10. Incomprehensibilities (21 letters)
Incomprehensibilities means impossible or incredibly difficult to comprehend. In the 1990s it set the record as the longest word “in common usage”, which seems almost incomprehensible when you think about it.
11. Sesquipedalianism (17 letters)
Although not the next longest word on the list, we simply had to include it. Sesquipedalianism is the practice of using long words in speech or writing.
An important note
There are some other long words that we could have included in this list of the longest words in English, and you may see some other words in different lists depending upon where you look. However, not all dictionaries will include highly technical, medical words so we have tried to avoid including these in our longest word list.
The longest English word in history?
Are you still thinking about supposedly the longest English word in history? Thought you might be! If you want to know the longest word in English, it’s spelled Methionylalanylthreonyl… You didn’t really think I was going to spell the whole thing out, did you? We’d both be here for hours! However, as a reminder, and if you want to know more about it, it’s the titin protein. This can be found in humans and is essential to the structure, development and elasticity of muscle. Its chemical name is 189,819 letters long.
If you want to hear how the longest word in English is pronounced, one hero has even made a YouTube video for it. So, settle in for a 1-hour epic and enjoy the longest English word pronunciation you’ll hear in your life!
A young MrBeast even had a go at pronouncing the longest word in English…
The longest conclusion
Don’t worry, I wasn’t really going to put you through the lonest conclusion in the English language after all that! Were you able to successfully pronounce any of the words?
For those of you who are ESL teachers or English language learners, having a go at these can be a great way to bring some fun into the classroom. You can also check out these ESL games for adults for more inspiration.