Acid:a chemical substance that neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive or sour-tasting liquid of this kind.
Hydronium:Hydronium is what you get when you put water and hydrogen ions together, forming H3O+ and also simplest form of oxonium, which is any ion that contains the trivalent oxygen cation.
I hope this is what you are looking for.