1. (from potential of Hydrogen) the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per litre; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and greater than 7 is more basic and less than 7 is more acidic)
   "The pH of the soil affects which plants will thrive in it";
   - pH scale

Derived forms: pHs

Type of: hydrogen ion concentration

Encyclopedia: PH