Word.ws English Dictionary

onium

/ˈoʊniəm/

onium noun: any cation derived by the addition of a proton to the hydride of any element of the nitrogen, chalcogen or halogen families.

Noun (1)

onium (plural oniums)

  1. Any cation derived by the addition of a proton to the hydride of any element of the nitrogen, chalcogen or halogen families.
  2. Any organic derivative of these compounds.

Noun (2)

US/ˈɒniəm/

onium (plural onia)

  1. The bound pair of a particle and its antiparticle.

Forms of onium

pluraloniums
pluralonia

Origin of onium

From ammonium.

See Wikipedia at muonium § Nomenclature.

Words formed from onium

Words that rhyme with onium

15 more rhymesFewer rhymes

Questions about onium

What does onium mean?
Onium means any cation derived by the addition of a proton to the hydride of any element of the nitrogen, chalcogen or halogen families.
What part of speech is onium?
Onium is a noun.
How do you pronounce onium?
Onium is pronounced /ˈoʊniəm/ (US).
What is the plural of onium?
The plural of onium is oniums.

Words near onium in the dictionary

  1. oniscophagous
  2. oniscophagy
  3. Onishi
  4. Onishis
  5. Onitsha
  6. onium
  7. oniums
  8. ONJ
  9. onjisaponin
  10. onjisaponins
  11. Onken

Source and license

Adapted from Wiktionary: onium (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Pronunciation audio from Wikimedia Commons, each file under its own free license: LL-Q1860 (eng)-Flame, not lame-onium.wav.

Cite this entry: “onium.” Word.ws, https://word.ws/onium. Based on Wiktionary, CC BY-SA 4.0.