13 of the Longest Words in the English Language

Some of the words that qualify for the title take hours to pronounce, like the 189,819-letter word for the protein Titin. Additionally, many of the longest words are medical terms, so we have excluded some of them to allow for more variety. The end result is a list of fascinatingly lengthy words that will make your vocabulary downright sesquipedalian.

01 Antidisestablishmentarianism

Part of Speech: noun

Definition: opposition to the disestablishment of the Church of England

Origins: While the word originated in 19th century Britain, it is now used to refer to any opposition to a government withdrawing support from a religious organization. Though rarely used in casual conversation, the word was featured in the Duke Ellington song, “You’re Just an Old Antidisestablishmentarianist.”

02 Floccinaucinihilipilification

Part of Speech: noun

Definition: the act of defining or estimating something as worthless

Origins: This word stems from the combination of four Latin words, all of which signify that something has little value: flocci, nauci, nihili, pilifi. This style of word creation was popular in Britain in the 1700s.

03 Pneumonoultramicroscopicsilicovolcanoconiosis

Part of Speech: noun

Definition: an invented word said to mean a lung disease caused by inhaling a fine dust

Origins: This word emerged in the late 1930s, and was said to be invented by Everett K. Smith, president of the National Puzzlers’ League, in an imitation of very long medical terms. It is not found in real medical usage.

04 Pseudopseudohypoparathyroidism

Part of Speech: noun

Definition: an inherited disorder similar to pseudohypoparathyroidism

Origins: This genetic disorder causes “short stature, round face and short hand bones,” according to the National Institutes of Health. Despite having a similar name, it is not the same as pseudohypoparathyroidism.

05 Psychoneuroendocrinological

Part of Speech: adjective

Definition: of or related to to the branch of science concerned with the relationships between psychology, the nervous system, and the endocrine system

Origins: This term was first seen in the 1970s in Journal of Neurological Science, a medical journal.

06 Sesquipedalian

Part of Speech: adjective

Definition: having many syllables or characterized by the use of long words

Origins: The Roman poet Horace used this term to caution young poets against relying on words that used a large number of letters. It was adopted in the 17th century by poets to ridicule their peers who used lengthy words.

07 Hippopotomonstrosesquippedaliophobia

Part of Speech: noun

Definition: fear of long words

Fun Fact: This word is most often used in humorous contexts. It is an extension of the word sesquipedalophobia, which has the same meaning and is more often used in a formal context.

08 Incomprehensibilities

Part of Speech: noun

Definition: things that are impossible to understand or comprehend

Fun Fact: In the 1990s, this word was named the longest word in common usage.

09 Uncopyrightable

Part of Speech: adjective

Definition: not able or allowed to be protected by copyright

Fun Fact: This word is one of the longest isograms (a word that does not repeat letters) in the English language.

10 Dermatoglyphics

Part of Speech: noun

Definition: the scientific study of hands, including fingerprints, lines, mounts, and shapes

Fun Fact: Unlike palmistry, this study is based in science and is often used in criminology as a way to identify both perpetrators and victims.

11 Euouae

Part of Speech: noun

Definition: a type of cadence in medieval music

Fun Fact: While this word might not look as impressive as others on this list, it’s the longest word in the English language to be composed entirely of vowels. (It’s also the word with the longest string of vowels.)

12 Psychophysicotherapeutics

Part of Speech: noun

Definition: a therapeutic approach that integrates both the mind and body

Fun Fact: While the Oxford Dictionary does not provide an official definition of this word, it is included on their list of the longest words in the English language.

13 Otorhinolaryngological

Part of Speech: adjective

Definition: of or relating to the medical specialization involving the ear, nose, and throat

Fun Fact: This medical specialization is more commonly known by its acronym, ENT.