Do you know what the longest English word is? That depends on who you ask. Different people have different rules for what a word is.


Some people would say the longest word in the English language is the chemical name for titin. Titin is the largest known protein; it’s found in human muscles. Because it’s a large and complex protein, it has a large and complex chemical name: It’s 189,819 letters long! You won’t find it in any dictionary, and most language experts say that the names of chemical formulas aren’t “real” words.

Just how long does it take to pronounce a word with 189,819 letters? Over three hours!


The longest word that you can find in an English dictionary has 45 letters: pneumonoultramicroscopicsilicovolcanoconiosis, a lung disease caused by inhaling fine ash and dust. The man who made up this word in 1935 was president of the National Puzzler’s League, an organization of people who enjoy word games. For this reason, some people don’t think it’s a “real” word, even though it is in the dictionary.


Another candidate for the longest word is hippopotomonstrosesquipedaliophobia, a 35-letter word that means “the fear of long words”. Many believe that this word was invented as a joke, so it’s not a “real” word. Whoever created this word clearly must have a sense of humor!


With 34 letters, supercalifragilisticexpialidocious is a word many Americans know. It was invented by songwriters for the 1964 Disney movie Mary Poppins. It’s also the title of a song in the movie, and the song explains that it’s a word to say when you don’t know what to say.


Finally, the longest English word that (1) appears in dictionaries and (2) wasn’t invented just to make a long word is pseudopseudohypoparathyroidism, a type of hormone disorder. It’s 30 letters long.

In conclusion

As you can see, English is full of strange long words. Furthermore, the long words are usually words that most of us don’t use in our everyday lives.

Which one do you think is the longest “real” word? What’s the longest English word that you know?