What is the Longest Word in the Dictionary?

Ever wondered what the longest word in the dictionary is? It’s pneumonoultramicroscopicsilicovolcanoconiosis, a 45‑letter monster that describes a lung disease caused by inhaling very fine silica dust from volcanoes.

While most people will never actually use it, major dictionaries include it as fun word trivia—often to show how word length can stretch far beyond everyday use.

This word was cleverly coined in 1935 by puzzle enthusiasts aiming to build the longest English word possible, and it later made its way into reference books like the Oxford English Dictionary and Merriam‑Webster once its usage met their editorial rules.

But it’s not used in daily conversation—and most medical experts simply call the actual disease silicosis.

In this article, we’ll unpack what this whopper of a word really means, explain how it is built from smaller parts, show you how to say it one syllable at a time, and share a few more record‑breaking words to satisfy your curiosity and fun facts.

What does pneumonoultramicroscopicsilicovolcanoconiosis mean?

This 45‑letter word names a rare lung disease caused by breathing in extremely fine silica particles—tiny dust that comes from volcanoes. In simple words, it's like getting sick from volcanic sand you can barely see.

Most experts just call the illness silicosis. A standard dictionary spelling of this elaborate term appeared in 1939, and today the word is recognized purely because of its length and dictionary presence.

How and why was this word created?

It wasn’t coined by doctors or scientists—instead, it was made in 1935 by §Everett Smith, president of the National Puzzlers’ League, as a joke long‑word.

The group wanted the longest English word, so they stitched together Latin and Greek roots like pneumono‑ (“lung”), ultra‑microscopic‑silico‑volcano‑coni‑osis (“dust‑disease”). Despite its playful origin, it showed up in major dictionaries and is still cited today as a record‑breaker, not a practical medical term.

5 Amazing Facts About this Word

Here are 5 simple and fun facts about pneumonoultramicroscopicsilicovolcanoconiosis:

1. It’s 45 letters long

This incredible term is the longest word you’ll find in major English dictionaries like Oxford and Merriam‑Webster.

2. It was invented in 1935

Not a medical expert, but Everett M. Smith, president of the National Puzzlers’ League, created it as a playful way to make the longest English word.

3. It’s built from many Greek and Latin parts

Each part adds meaning: pneumono‑ “lung”, ultra‑ “beyond”, micro‑scopic‑silico‑volcano‑cone‑iosis (fine volcanic dust disease). Put together, it “means” a lung disease from volcanic silica dust.

4. It’s a made-up disease

Doctors never use this term. Real experts call the condition silicosis, a serious lung illness from silica dust—but not specifically volcanic dust.

5. It made it into dictionaries

Thanks to promotion by the Puzzlers’ League, it first appeared in the Oxford English Dictionary in 1936 and was added to Merriam‑Webster in 1939, even though nobody actually uses it in medicine