The full meaning of pH is Power of Hydrogen. The hydrogen molecules in a substance determine its acidic or basic nature. Meaning, if the pH of a liquid or product is 1 or 2 then it is acidic and if the pH is 13 or 14 then it is alkaline. If pH is 7 then it is neutral. pH stands for 'potential of hydrogen' or 'power of hydrogen'. It is a scale used to specify the acidic nature or basicity of an aqueous solution. Acidic solutions (solutions with high concentration of H ions) are measured to have a lower pH value than basic or alkaline solutions. If we talk about the human body, pH balance plays an important role in the chemical makeup of the human body. The term 'pH' refers to whether a substance is an acid, an alkaline (also called basic) or neutral .