hydronium

Noun

 * 1)  The hydrated hydrogen ion, H$3$O$+$.

Usage notes
May also be defined as the simplest of a class of oxygen cations with three bonds (i.e., the simplest form of oxonium).

Translations

 * Danish: oxonium
 * Finnish: ,
 * Italian:, idrossonio
 * Japanese: ヒドロニウム
 * Spanish: hidronio