any of three stereoisomeric acids having the formula C 8 H 8 O 3 , especially dl-mandelic acid, a white, crystalline, slightly water-soluble solid obtainable from amygdalin: used chiefly in medicine as an antiseptic.
mandelic acid man·del·ic acid (mān-děl'ĭk) n. An acid that has both antibacterial and bacteriostatic properties, used in treating urinary tract infections.