Hydron is the name for positive hydrogen ions without regard to nuclear mass, or positive ions formed from natural hydrogen (hydrogen that has not been subjected to isotope separation).
Traditionally, the term "proton" was and is used in place of "hydron", by itself and in many chemical terms. However, such usage is technically incorrect, as only 99.999% of natural hydrogen nuclei are protons; the rest are deuterons and rare tritons.
Hydron was defined by IUPAC in 1988.
The negatively-charged counterpart of the hydron is the hydride anion, H-.
Proton, having the symbol p or 1H+, refers only to the +1 ion of protium, 1H.
Deuteron, having the symbol 2H+ or D+, refers only to the +1 ion of deuterium, 2H or D.
Triton, having the symbol 3H+ or T+, refers only to the +1 ion of tritium, 3H or T.