ph

/piː eɪtʃ/
noun
  1. A measure of how acidic or basic a substance is, on a scale from 0 (very acidic) to 14 (very basic), with 7 being neutral.
    • The pH of pure water is 7, which is neutral.
    • Gardeners often test the pH of the soil to see if it is right for growing plants.
    • Lemon juice has a low pH, making it very acidic.