pH
noun [ C usually singular ] uk/ˌpiːˈeɪtʃ/ us/ˌpiːˈeɪtʃ/
酸碱度，pH 值
a number that shows how strongly acid or alkaline a substance is, in a range from 0 to 14
Below pH 6.5 is acid, above pH 7.5 is alkaline. pH值低于6.5为酸性，高于7.5为碱性。
The soil in our garden has a low/high pH. 我们花园里的土壤pH值较低／高。