20 Longest Words in English and Their Meanings (Plus, How To Pronounce Them!)

Back in grade school, words like "onomatopoeia" and "supercalifragilisticexpialidocious" seemed insanely complicated and long. Surprisingly, neither of these is the longest word in English. But, Parade is here to tell you the longest word, accompanied by the 20 longest words in English and their meanings.

The English language is vast, eclectic and a little bit complicated. Among the many words in the dictionary, some stand out not just for their meanings—but for their sheer length. These lengthy words often intrigue and challenge even your favorite Spelling Bee champs. 

The longest English words are often rooted in specialized fields, like medicine and literature. Of course, there are exceptions to this rule. From technical to whimsical,  prepare for your vocabulary to be stretched with 20 of the longest words in English. Plus, find out what they mean.

Related: 55 Examples of Onomatopoeia

What Is the Longest Word in English?

Drum roll, please! Any guesses? The longest word in English is "pneumonoultramicroscopicsilicovolcanoconiosis." According to Dictionary.com, this is the longest word that appears in an English dictionary and is 45 letters long.

What Does the Longest Word in English Mean?

Now that we know "pneumonoultramicroscopicsilicovolcanoconiosis'" is the longest word in English, what does the longest word in English mean? It is a type of lung disease caused by the inhalation of fine silicate or quartz dust, often found in volcanoes.

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20 Longest Words in English and What They Mean

20. Trichotillomania

Pronunciation: trik-oh-til-oh-may-nee-uh
Meaning: The urge to pull your own hair.
Letters: 16

19. Xenotransplantation

Pronunciation: zee-noh-trans-plan-tay-shun
Meaning: A procedure that involves transplanting living cells, tissues or organs from one species to another.
Letters: 19

18. Incomprehensibility

Pronunciation: in-com-pree-hen-sib-il-it-ee
Meaning: The state of being difficult to understand.
Letters: 19

17. Uncharacteristically

Pronunciation: un-char-ac-ter-is-ti-cal-ly
Meaning: Not typical of a particular person or thing.
Letters: 20

16. Disproportionableness

Pronunciation: dis-pro-por-tion-a-ble-ness
Meaning: The state of being out of proportion; out of order. 
Letters: 21

15. Counterrevolutionaries

Pronunciation: coun-ter-rev-o-lu-tion-ar-ies
Meaning: Individuals who participate in or support a movement or action aimed at overthrowing a government or social system.
Letters: 22

14. Dichlorodifluoromethane

Pronunciation: di-chlo-ro-di-flu-o-ro-me-thane
Meaning: A chlorofluorocarbon compound known for its role in ozone depletion.
Letters: 23

13. Microspectrophotometries

Pronunciation: mi-cro-spec-tro-pho-to-me-tries
Meaning: The measurement of spectra of microscopic samples using spectrophotometry.
Letters: 24

12. Laryngotracheobronchitis

Pronunciation: la-ryn-go-tra-che-o-bron-chi-tis
Meaning: Inflammation of the larynx, trachea, and bronchi.
Letters: 24

11. Thyroparathyroidectomized

Pronunciation: thai-roh-para-thai-roi-dek-tuh-maizd
Meaning: Excision of both the thyroid and parathyroid glands.
Letters: 25

10. Honorificabilitudinitatibus

Pronunciation: ho-no-ri-fi-ca-bi-li-tu-di-ni-ta-ti-bus
Meaning: The state of being able to achieve honors.
Letters: 27

9. Psychoneuroendocrinological

Pronunciation: sy-coh-nyoo-roh-en-do-crin-uh-log-ic-uhl 
Meaning: Relating to the study of the interaction between psychological processes and the nervous and endocrine systems.
Letters: 27

8. Antidisestablishmentarianism

Pronunciation: anti-dis-es-tab-lish-ment-ar-i-an-is-m
Meaning: A political position that originated in 19th-century Britain opposing proposals for the disestablishment of the Church.
Letters: 28

7. Spectrophotofluorometrically

Pronunciation: speck-tro-foe-toe-flure-o-met-rick-ly
Meaning: A way of measuring light.
Letters: 28

6. Floccinaucinihilipilification

Pronunciation: flaa-suh-now-suh-nai-uh-luh-pi-luh-fuh-kay-shn
Meaning: The estimation of something as worthless.
Letters: 29

5. Eellogofusciouhipoppokunurious

Pronunciation: ee-loh-goh-fuh-shee-oh-hip-oh-poh-kyoo-noo-ree-uhs
Meaning: Very good, very fine.
Letters: 30

4. Pseudopseudohypoparathyroidism

Pronunciation: soo-dow-soo-dow-hai-pow-peh-ruh-thai-roy-di-zm
Meaning: An inherited condition that causes short stature, round face and short hand bones.
Letters: 30

3. Supercalifragilisticexpialidocious

Pronunciation: soo-pr-ka-luh-fra-juh-li-stuhk-ek-spee-a-luh-dow-shuhs
Meaning: Extraordinarily good or wonderful.
Letters: 34

2. Hippopotomonstrosesquippedaliophobia

Pronunciation: hi-puh-paa-tuh-muhn-strow-suh-skwipt-a-lee-ow-fow-bee-uh
Meaning: The fear of long words.
Letters: 36

1. Pneumonoultramicroscopicsilicovolcanoconiosis

Pronunciation: noo-muh-noh-ul-truh-my-kroh-skop-ik-sil-i-koh-vol-kay-noh-koh-nee-oh-sis
Meaning: A lung disease caused by the inhalation of fine silicate or quartz dust, often found in volcanoes.
Letters: 45

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