What is the Longest English Word?

中文

For those who are familiar with Mary Poppins, they must have heard of the song — Supercalifragilisticexpialidocious. In this Ed’s Elevenses blog post, let’s find out whether or not it is the longest English word to date.

Supercalifragilisticexpialidocious (adjective; also supercalifragilistic) is defined as extraordinarily good or wonderful.

For example:
✅ We had a supercalifragilistic time at the party!
✅ It’s absolutely supercalifragilisticexpialidocious that our local team won the Premier League.

However, it only contains 34 letters, so it is not the longest word.

The longest word in major English dictionaries is pneumonoultramicroscopicsilicovolcanoconiosis (45 letters), which is a technical term and is a synonym for the lung disease—caused by inhaling very fine ash and sand dust found in most volcanoes—known as silicosis.

For non-technical words in major dictionaries, editors usually regard flocci­nauci­nihili­pili­fication (29 letters) as the longest one, which is defined as the estimation of something as worthless/not at all useful.

In everyday situations, you are unlikely to come across these very long words in general text. Some studies suggest that the longest words we, as casual readers, may encounter on a day-to-day basis are uncharacteristically and internationalisation, which both have 20 letters.

Uncharacteristically (adverb): In a way that is not typical of someone or something.
Internationalisation (noun): The process of making something international.

Similar to how translators often abbreviate the word “translation” to “t9n”, with “9” indicating the number of letters between the first and the last, “internationalisation” can be shortened to “i18n”.

Isn’t it supercalifragilisticexpialidocious that you now know answers to questions about the longest words in the English language?

Since you have made this far, here is an additional fun fact: The longest place name in Britain is the 58-letter place name in Wales, Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch, of which pronunciation can be listened to here.

You may be interested in: What is the Longest Word with No Repeated Letters?

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Edison Tam MA MCIL CL is a Translator, Proofreader, and Copyeditor (zh-hk/en) who works with students, independent non-fiction writers, academic researchers, and clients from businesses and organisations of all sizes.

He is Chartered Linguist and Member of the Chartered Institute of Linguists (CIOL), and has undergone wide-ranging academic training in Business, Modern Languages, and Applied Linguistics in Hong Kong, London, and Barcelona.