n.
Pronunciation: ' p ē - ' ā ch
Function: noun
Etymology: German, from P otenz power + H (symbol for hydrogen)
Date: 1909
: a measure of acidity and alkalinity of a solution that is a number on a scale on which a value of 7 represents neutrality and lower numbers indicate increasing acidity and higher numbers increasing alkalinity and on which each unit of change represents a tenfold change in acidity or alkalinity and that is the negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity in gram equivalents per liter of the solution also : the condition represented by a pH number