Learner's definition of PH
[singular] technical
: a number between 0 and 14 that indicates if a chemical is an acid or a base*pH值（介于0~14之间，表述化学品酸碱度的数值） ◊ A chemical with a pH lower than 7 is an acid, and a chemical with a pH higher than 7 is a base.*pH值低于7的化学品是酸性，高于7的是碱性。