'Phthalic acid' definitions:

Definition of 'phthalic acid'

From: WordNet
noun
A colorless acid used to make dyes and perfumes

Definition of 'Phthalic acid'

From: GCIDE
  • Phthalic \Phthal"ic\, a. [Naphthalene + -ic.] (Chem.) Pertaining to, or designating, a dibasic acid obtained by the oxidation of naphthalene and allied substances. [1913 Webster]
  • Phthalic acid (Chem.), a white crystalline substance, C6H4.(CO2H)2, analogous to benzoic acid, and employed in the brilliant dyestuffs called the phthaleins. [1913 Webster]