Wiktionary
n. 1 (context chemistry English) (&lit hydrogen ion English) ; H- or H+ 2 (context chemistry English) a proton combined with one or more water molecules; usually written H3O+ and called the hydronium ion though is best considered as H9O4+ but is often written H+(aq) for simplicity 3 (context chemistry English) a bare hydrogen nucleus; a proton , deuteron or triton
WordNet
n. a positively charged atom of hydrogen; that is to say, a normal hydrogen atomic nucleus
Wikipedia
A hydrogen ion is created when a hydrogen atom loses its electron. A lone hydrogen ion (or proton) can readily combine with other particles and therefore is only seen isolated when it is in a gaseous state or a nearly particle free space. Due to its extremely high charge density of approximately 2E10 times that of a Sodium ion, the bare hydrogen ion cannot exist freely in solution as it readily hydrates (bonds quickly). The hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes. Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions.
Usage examples of "hydrogen ion".
Saltiness is stimulated by many inorganic ions other than the hydrogen ion, of course.
Thatll force the pH down-if only hydrogen ion activity means something here.
One of the four nucleotides in the DNA has a hydroxyl radical where DNA nucleotides on Earth just have a hydrogen ion.
That'll force the pH down - if only hydrogen ion activity means something here.
Protons and electrons in the Van Allen belts, the solar wind, neutrons, quasar radio bursts, hydrogen ion emissions, the entire electromagnetic spectrum—.
The prime-field of a hydrogen ion, passing through my body in warp, might displace the prime-fields of half a dozen of my atoms, and they in turn might displace to a lesser degree the fields of two dozen more atoms before the shockwave passed through my skin and dispersed.
Spectroscopic analysis showed the drive was a hydrogen ion stream with traces of carbon, possibly from the refractor.