* Acids have a higher concentration of hydrogen ions (H+) than hydroxide ions (OH-).

* Bases have a higher concentration of hydroxide ions (OH-) than hydrogen ions (H+).

* Salts are formed by the reaction of an acid and a base, and they typically contain a cation (positive ion) and an anion (negative ion) other than H+ or OH-.

In summary: A substance with more OH- ions than H+ ions is a base.