The acid potential of aqueous solutions is measured in terms of the pH scale. The symbol "p" means take the negative logarithm of whatever follows in the formula for pH, pO, p[anything].
We can define the pOH as
pOH = - log [OH-]
In words, the pOH is the negative logarithm of the hydroxide ion concentration.
pOH is a measure of the alkalinity of a solution. Aqueous solutions at 25
degrees Celsius with pOH less than 7 are alkaline, pOH greater than 7 are
acidic and pOH equal to 7 are neutral.