parahydrogen

par·a·hy·dro·gen
P3A1R1A1H4Y4D2R1O1G2E1N1
UK/ˌpæɹəˈhaɪdɹəd͡ʒ(ə)n/US/ˌpɛɹəˈhaɪdɹəd͡ʒ(ə)n/

noun

The form of the hydrogen molecule (H₂) in which the two nuclei have antiparallel spin; about 25% of hydrogen at room temperature.

Opposite
orthohydrogen
OriginEnglish hydrogen ← French hydrogène ← Ancient Greek γένος (génos) →
Scrabble 22
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Meanings

nounparahydrogen (countable and uncountable, plural parahydrogens)

plural parahydrogens

  1. countableuncountablenatural sciencesThe form of the hydrogen molecule (H₂) in which the two nuclei have antiparallel spin; about 25% of hydrogen at room temperature.

Synonyms & antonyms

Opposite
orthohydrogen

Origin

  1. Proto-Indo-European*per-
  2. Proto-Indo-European*preh₂-
  3. Proto-Hellenic*pərai
  4. Ancient Greekπᾰρᾰ́ (părắ)
  5. Ancient Greekπᾰρᾰ- (pără-)
  6. Englishpara-
  7. Proto-Indo-European*wed-
  8. Proto-Indo-European*wódr̥
  9. Proto-Hellenic*údōr
  10. Ancient Greekῡ̆̔́δωρ (hū̆́dōr)
  11. Ancient Greekὑδρο- (hudro-)
  12. Frenchhydro-
  13. Proto-Indo-European*ǵenh₁-
  14. Proto-Indo-European*ǵénh₁os
  15. Proto-Hellenic*génos
  16. Ancient Greekγένος (génos)
  17. Frenchhydrogène
  18. Englishhydrogen
  19. Englishparahydrogen

From para- + hydrogen.

Full word history & related roots →

Rhymes & wordplay

Rhymes with parahydrogen

hydrogendihydrogenhyperhydrogen
All rhymes →
Cite this entry
APA

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

MLA

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

Chicago

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

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