diphenhydramine

D2I1P3H4E1N1H4Y4D2R1A1M3I1N1E1
UK/ˌdʌɪ.fɛnˈhʌɪ.dɹəm.iːn/US/ˌdaɪˌfɛnˈhaɪ.dɹəˌmiːn/

noun

An antihistamine and anticholinergic drug that blocks the effect of histamine at H₁ receptor sites, relieving allergy symptoms. It also reduces smooth muscle contraction, increases heart rate, and sedates the user by blocking muscarinic acetylcholine receptors (mAChRs).

“Diphenhydramine is a convenient and cheap antihistamine for use, but there are other drugs that do not make the user tired.”

Similar
ZzzQuilBenadryl
OriginEnglish amine ← Latin ammoniacus ← Ancient Greek Ᾰ̓́μμων (Ắmmōn) →
UncommonScrabble 30
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Meanings

noundiphenhydramine (countable and uncountable, plural diphenhydramines)

plural diphenhydramines

  1. countableuncountablemedicineAn antihistamine and anticholinergic drug that blocks the effect of histamine at H₁ receptor sites, relieving allergy symptoms. It also reduces smooth muscle contraction, increases heart rate, and sedates the user by blocking muscarinic acetylcholine receptors (mAChRs).

    Diphenhydramine is a convenient and cheap antihistamine for use, but there are other drugs that do not make the user tired.

    Synonyms: ZzzQuil, Benadryl

Synonyms & antonyms

nounAn antihistamine and anticholinergic drug that blocks the effect of histamine at H₁ receptor sites, relieving allergy symptoms. It also reduces smooth muscle contraction, increases heart rate, and sedates the user by blocking muscarinic acetylcholine receptors (mAChRs).

Similar
ZzzQuilBenadryl

More synonyms by meaning

nounantihistamine (trade name Benadryl) used to treat allergic reactions involving the nasal passages (hay fever) and also to treat motion sickness

Similar
Benadryl
Broader
antihistamine
Also see
benadryl

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

  1. Proto-Indo-European*dwóh₁
  2. Proto-Indo-European*dwi-
  3. Proto-Hellenic*dwi-
  4. Ancient Greekδῐ- (dĭ-)
  5. Latindi-
  6. Englishdi-
  7. Proto-Indo-European*bʰeh₂-
  8. Proto-Indo-European*bʰh₂nyéti
  9. Proto-Hellenic*pʰáňňō
  10. Ancient Greekφαίνω (phaínō)
  11. Frenchphéno-
  12. Proto-Indo-European*swel-der.?
  13. Ancient Greekῡ̔́λη (hū́lē)
  14. Frenchphényle
  15. Englishphenyl
  16. Englishdiphen(yl)
  17. English(benz)hydr(yl)
  18. Egyptianjmn
  19. Ancient GreekᾸ̓́μμων (Ắmmōn)
  20. LatinAmmōn
  21. Latinammoniacus
  22. Englishammonia
  23. Englishamine
  24. Englishdiphenhydramine

From diphen(yl) + (benz)hydr(yl) + -amine.

Full word history & related roots →

Translations

Chinese Mandarin 苯海拉明
  • 苯海拉明 (běnhǎilāmíng)antihistamine and sedative drug
Czech difenhydramin
  • difenhydraminantihistamine and sedative drug
Cite this entry
APA

diphenhydramine. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/diphenhydramine

MLA

“diphenhydramine.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/diphenhydramine. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “diphenhydramine,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/diphenhydramine.

Source: diphenhydramine on Wiktionary, CC BY-SA 4.0.