30 Longest Words in the English Language

The English language is home to more than 170,000 words in current use and thousands more that are considered obsolete or archaic. Among these, some words stand out for their sheer length stretching across the page with dozens of letters. Many of these tongue-twisters come from scientific terminology, medical conditions, or playful coinages designed to test the limits of language itself. While you may never use these words in daily conversation, they showcase the creativity, complexity, and quirks of English vocabulary.

Below is a list of 30 of the longest words in English, along with their definitions and origins.

1. Pneumonoultramicroscopicsilicovolcanoconiosis (45 letters)

• Origin: Coined in 1935 by the president of the National Puzzlers’ League.
• Meaning: A lung disease caused by inhaling fine silica particles, often from volcanic ash or mines.

2. Hippopotomonstrosesquipedaliophobia (36 letters)

• Origin: Modern humorous invention, blending Greek and Latin roots.
• Meaning: The ironic fear of long words themselves.

3. Supercalifragilisticexpialidocious (34 letters)

• Origin: Popularized in the 1964 Disney film Mary Poppins.
• Meaning: A whimsical word meaning “fantastic” or “wonderful beyond imagination.”

4. Pseudopseudohypoparathyroidism (30 letters)

• Origin: Scientific medical terminology.
• Meaning: A mild inherited disorder resembling pseudohypoparathyroidism but without abnormal hormone levels.

5. Floccinaucinihilipilification (29 letters)

• Origin: Created in the 18th century at Eton College, from Latin fragments.
• Meaning: The act of considering something worthless or trivial.

6. Antidisestablishmentarianism (28 letters)

• Origin: 19th-century England during church–state debates.
• Meaning: A political movement opposing the separation of the Church of England from the state.

7. Honorificabilitudinitatibus (27 letters)

• Origin: Latin; famously used by Shakespeare in Love’s Labour’s Lost.
• Meaning: The state of being able to achieve honors.

8. Electroencephalographically (27 letters)

• Origin: Medical terminology, from Greek roots electro (electricity) and encephalo (brain).
• Meaning: Relating to the recording of brain activity via electrodes (EEG).

9. Psychoneuroendocrinological (27 letters)

• Origin: Modern medical/scientific English.
• Meaning: Pertaining to interactions between the mind, nervous system, and hormones.

10. Spectrophotofluorometrically (28 letters)

• Origin: Scientific English, from Latin and Greek roots.
• Meaning: Relating to the measurement of fluorescence with a spectrophotofluorometer.

11. Thyroparathyroidectomized (25 letters)

• Origin: Medical English.
• Meaning: Having had the thyroid and parathyroid glands surgically removed.

12. Anticonstitutionalistically (25 letters)

• Origin: Borrowed from French anticonstitutionnellement.
• Meaning: Acting in a way that is against constitutional principles.

13. Radioimmunoelectrophoresis (25 letters)

• Origin: Scientific English.
• Meaning: A lab technique using radioactive and immune processes to separate proteins.

14. Psychophysicotherapeutics (25 letters)

• Origin: Greek roots psyche (mind), physis (nature), therapeia (healing).
• Meaning: Treatment of disease using both psychological and physical methods.

15. Hepaticocholangiogastrostomy (28 letters)

• Origin: Greek medical roots.
• Meaning: A surgical connection between the liver, bile ducts, and stomach.

16. Dacryocystorhinostomy (24 letters)

• Origin: Greek dakryon (tear), rhinos (nose), stoma (opening).
• Meaning: A surgical operation creating a passage between the tear sac and the nasal cavity.

17. Otorhinolaryngological (22 letters)

• Origin: Greek roots oto (ear), rhino (nose), larynx (voice box).
• Meaning: Relating to the study of diseases of the ear, nose, and throat.

18. Deinstitutionalization (22 letters)

• Origin: Modern English.
• Meaning: The process of reducing reliance on large institutions (like psychiatric hospitals) in favor of community care.

19. Counterrevolutionaries (21 letters)

• Origin: From French during the Revolution period.

• Meaning: People who actively oppose a revolution.

20. Incomprehensibilities (21 letters)

• Origin: Latin in- (not) + comprehendere (to grasp/understand).
• Meaning: Things that are impossible or very difficult to understand.

21. Transubstantiationalist (24 letters)

• Origin: Latin religious roots.
• Meaning: Someone who believes in or supports the doctrine of transubstantiation.

22. Polyphiloprogenitive (20 letters)

• Origin: Coined by poet T. S. Eliot from Greek poly (many) + philo (love) + progeny (offspring).
• Meaning: Extremely prolific in producing children or creations.

23. Overintellectualization (23 letters)

• Origin: Modern English.
• Meaning: The act of overanalyzing something in an excessively intellectual way.

24. Hyperimmunoglobulinemia (25 letters)

• Origin: Medical Greek/Latin.
• Meaning: A condition marked by too many immunoglobulins (antibodies) in the blood.

25. Mischaracterization (20 letters)

• Origin: English, from mis- + character.
• Meaning: The act of giving a false or misleading description of something.

26. Disproportionableness (21 letters)

• Origin: Latin proportio (measure, relation).
• Meaning: The quality of being out of proportion.

27. Antituberculosises (20 letters)

• Origin: Scientific Latin.
• Meaning: Treatments or measures against tuberculosis.

28. Insubordinationaries (20 letters)

• Origin: Latin subordinare (to place under).
• Meaning: People who consistently resist or defy authority.

29. Uncharacteristically (20 letters)

• Origin: 19th-century English.
• Meaning: Acting in a way that is not typical of one’s usual behavior.

30. Deinstitutionalizing (20 letters)

• Origin: Modern English.
• Meaning: The act of moving away from institutional systems toward community-based services.

31. Dichlorodifluoromethane (23 letters)

• Origin: Chemical nomenclature.
• Meaning: A chlorofluorocarbon (CFC) once used as a refrigerant and propellant.

32. Psychopharmacological (22 letters)

• Origin: Greek psyche (mind) + pharmakon (drug).
• Meaning: Relating to the study of how drugs affect the mind and behavior.

33. Immunoelectrophoretically (25 letters)

• Origin: Medical English.
• Meaning: Pertaining to the separation of proteins in blood using immunoelectrophoresis.

34. Trinitrophenylmethylnitramine (29 letters)

• Origin: Chemical term.

• Meaning: The full chemical name for TNT (trinitrotoluene).

35. Psychotherapeutics (20 letters)

• Origin: Greek psyche (soul/mind) + therapeia (healing).
• Meaning: Treatment of mental or emotional disorders by psychological methods.

36. Xenotransplantation (21 letters)

• Origin: Greek xeno (foreign) + transplant.
• Meaning: The transplantation of organs or tissues between different species.

37. Tergiversationists (20 letters)

• Origin: Latin tergiversari (to turn one’s back).
• Meaning: People who are evasive, shifty, or constantly change their opinions.

38. Chrononhotonthologos (21 letters)

• Origin: Coined by Henry Carey in 1734 as a comic play title.
• Meaning: A deliberately long, pompous word with no real meaning used satirically.

39. Psychophysiological (21 letters)

• Origin: Greek psyche (mind) + physis (nature).
• Meaning: Relating to how the mind influences the body’s functions.

40. Tetramethyldiampinidine (23 letters)

• Origin: Chemical naming system.
• Meaning: A complex organic compound used in chemical reactions.

41. Acetylphenylhydrazine (22 letters)

• Origin: Chemistry.
• Meaning: A chemical compound used in organic synthesis.

42. Hexamethylenetetramine (22 letters)

• Origin: Chemistry.
• Meaning: A crystalline compound used as a fuel tablet and in medicine.

43. Dihydroxyacetonephosphate (27 letters)

• Origin: Biochemistry.
• Meaning: An intermediate compound in cellular metabolism.

44. Hepatogastroenterostomy (25 letters)

• Origin: Medical, from Greek hepato (liver), gastro (stomach), entero (intestine).
• Meaning: A surgical connection between the liver, stomach, and intestine.

45. Archaeopterygiformes (23 letters)

• Origin: Paleontology.

• Meaning: An extinct order of birds, including the Archaeopteryx.

46. Cryptococcosis (20 letters)

• Origin: Greek kryptos (hidden) + kokkos (berry).
• Meaning: A fungal disease caused by Cryptococcus species.

47. Trichotillomania (20 letters)

• Origin: Greek tricho (hair) + tillein (to pull).
• Meaning: A disorder where people compulsively pull out their own hair.

48. Hematospectrophotometry (26 letters)

• Origin: Medical science.
• Meaning: The measurement of hemoglobin in blood using spectrophotometry.

49. Sulphogermanate (20 letters)

• Origin: Chemistry.
• Meaning: A type of chemical salt containing sulfur and germanium.

50. Dermatoglyphics (20 letters)

• Origin: Greek derma (skin) + glyph (carving).
• Meaning: The scientific study of fingerprints and skin ridge patterns.