<chemistry> Pertaining to, or designating, a dibasic acid obtained by the oxidation of naphthalene and allied substances.

<chemistry> Phthalic acid, a white crystalline substance, C6H4.(CO2H)2, analogous to benzoic acid, and employed in the brilliant dyestuffs called the phthaleins.

Origin: Naphthalene + -ic.

(01 Mar 1998)