What Is the Longest Word in the English Language?

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Do you know what the longest word in the English language is? Contrary to popular belief, it is not supercalifragilisticexpialidocious, no matter how fun it is to pronounce in song. In fact, it only ranks third on the list. Instead, the actual word is significantly less cheery.

The longest word in the English dictionary is pneumonoultramicroscopicsilicovolcanoconiosis, which refers to a disease that causes inflammation of the lungs after inhaling microscopic silicate or quartz dust. Each part of the 45-letter word can be broken down to find its true meaning, with the prefix ‘pneumono' coming from the ancient Greek word for lung.

As is rather common, the individual components of the word come from ancient Greek and Latin, making those who studied these languages whizzes at deciphering the long combination of letters.

Surprisingly, pneumonoultramicroscopicsilicovolcanoconiosis didn't even start out as a legitimate word. It was coined in 1935 by then-president of the National Puzzlers' League Everett M. Smith before finding its way into the dictionary several years later. However, the condition that the word describes is very real, and it is sometimes used as a synonym for silicosis, an occupational disease that normally impacts miners and other stone workers.

If you have no idea how to say pneumonoultramicroscopicsilicovolcanoconiosis, you're not alone. The 19-syllable word can be extremely difficult to pronounce, even for native English speakers. But if you really want to impress your inner circle with your linguistic knowledge, do not despair because the phonetic spelling of the word is pneu-mo-no-ul-tra-mi-cro-scop-ic-si-li-co-vol-ca-no-co-ni-o-sis.

Curious about what other English words rank in terms of length? Here are a few other long words to add to your vocabulary list: hippopotomonstrosesquippedaliophobia (36 letters), pseudopseudohypoparathyroidism (30 letters), floccinaucinihilipilification (29 letters), antidisestablishmentarianism (28 letters).

Ironically enough, one of these words—hippopotomonstrosesquippedaliophobia—is actually the fear of long words. While not all of these words meet the requirements to be included in the English dictionary, they're still noteworthy.