məˈlēik, -lāik- noun
Etymology: maleic from French maléique (in acide maléique maleic acid), alteration of malique malic (in acide malique malic acid) — more at malic acid
: a crystalline unsaturated dicarboxylic acid HOOCCH . CHCOOH obtained usually by catalytic oxidation of benzene or naphthalene or by dehydration of malic acid and used chiefly in making polyester resins; cis -butene-dioic acid — compare cis-trans isomerism a, fumaric acid