Longest Words in English

Discover some of the longest and most complex words in the English language.

Did You Know?

The longest word in major English dictionaries is pneumonoultramicroscopicsilicovolcanoconiosis with 45 letters. However, chemical names can be much longer - the full chemical name for the protein titin has 189,819 letters and would take over 3 hours to pronounce!

Pneumonoultramicroscopicsilicovolcanoconiosis

45 letters

Definition: A lung disease caused by inhaling very fine silica particles, specifically from a volcano.

Category: Medical/Technical

Pronunciation: nu-muh-noh-ul-truh-my-kruh-skop-ik-sil-i-koh-vol-kay-noh-koh-nee-oh-sis

Hippopotomonstrosesquippedaliophobia

36 letters

Definition: The fear of long words (ironically, a very long word itself).

Category: Psychology

Pronunciation: hip-poh-pot-oh-mon-stroh-ses-kwip-ped-ay-lee-oh-foh-bee-uh

Supercalifragilisticexpialidocious

34 letters

Definition: Extraordinarily good; wonderful (from Mary Poppins).

Category: Pop Culture

Pronunciation: soo-per-kal-uh-fraj-uh-lis-tik-eks-pee-al-uh-doh-shus

Pseudopseudohypoparathyroidism

30 letters

Definition: A mild form of inherited pseudohypoparathyroidism.

Category: Medical

Pronunciation: soo-doh-soo-doh-hy-poh-par-uh-thy-roid-iz-um

Floccinaucinihilipilification

29 letters

Definition: The action or habit of estimating something as worthless.

Category: Formal/Literary

Pronunciation: flok-si-naw-si-ni-hil-i-pil-i-fi-kay-shun

Antidisestablishmentarianism

28 letters

Definition: Opposition to the disestablishment of the Church of England.

Category: Political/Historical

Pronunciation: an-tee-dis-es-tab-lish-men-tair-ee-an-iz-um

Longest Dictionary Word

Pneumonoultramicroscopicsilicovolcanoconiosis is the longest word appearing in major English dictionaries.

It was coined specifically to be the longest word and refers to a lung disease.

Longest Common Word

Antidisestablishmentarianism at 28 letters is often considered the longest non-technical word in common use.

It relates to 19th-century British politics and the Church of England.

Fun Facts About Long Words

  • Many of the longest words are medical or scientific terms
  • Some long words were created specifically to be long (like pneumonoultramicroscopicsilicovolcanoconiosis)
  • German is famous for very long compound words that can be created on the fly
  • The longest place name is "Taumatawhakatangihangakoauauotamateaturipukakapikimaungahoronukupokaiwhenuakitanatahu" in New Zealand (85 letters)