buffering agent
weak acid or base used to maintain the acidity (pH) of a solution near a chosen value after the addition of another acid or base
en-GB/ˈbʌfəɹɪŋ æʒɒn/
en-US/ˈbʌfɚɪŋ ˈeɪd͡ʒənt/
weak acid or base used to maintain the acidity (pH) of a solution near a chosen value after the addition of another acid or base