Does the concentration of an acid or base refer to the presence of H3O plus ions in solution?

An acid solution is a solution that contains more hydronium (H3O+) ions than hydroxide (OH-) ions. On the other hand, the reverse is true for a basic solution. Acidic solutions will have a pH less than 7 whereas basic solutions will have a pH greater than 7 by the equation pH=-log[H3O+].