PHTHALIC

Phthal″ic (?), a. [[Naphthalene + -ic.]] (Chem.) Pertaining to, or designating, a dibasic acid obtained by the oxidation of naphthalene and allied substances. Phthalic acid (Chem.), a white crystalline substance, C6H4.(CO2H)2, analogous to benzoic acid, and employed in the brilliant dyestuffs called the phthaleins.