Standard Lemma guide

hydronium

noun · 1 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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  • Received-Pronunciation: /haɪˈdɹəʊ.ni.əm/
  • General-American: /haɪˈdɹoʊ.ni.əm/
  • UK: Recorded audio is listed in the source snapshot.
  • rhymes with -əʊniəm

1

noun

Meaning 1

The hydrated hydrogen ion, H3O+.

Definition source: English Wiktionary via Wiktextract

Usage: physical

Topics: chemistry, inorganic-chemistry, natural-sciences, physical-sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

Etymology tree Proto-Indo-European *wed- Proto-Indo-European *-r̥ Proto-Indo-European *wódr̥ Proto-Hellenic *údōr Ancient Greek ῡ̆̔́δωρ (hū̆́dōr) Ancient Greek ῠ̔δρο- (hŭdro-)der. English hydro- New Latin ammōniumbor. English ammonium English onium English hydronium From hydro- + onium.

Across languages

Translations

10 source translations are retained for this English entry.

  • Chinese Mandarin: 水合氫離子 /水合氢离子 (shuǐhé qīng lízǐ) — H3O+
  • Danish: oxonium — H3O+
  • Finnish: hydronium — H3O+
  • Finnish: hydroksonium — H3O+
  • German: Hydronium — H3O+
  • Italian: idronio — H3O+
  • Italian: idrossonio — H3O+
  • Japanese: ヒドロニウム (hidoroniumu) — H3O+
  • Northern Kurdish: hîdronyûm — H3O+
  • Spanish: hidronio — H3O+