- a yellow, water-insoluble, crystalline powder, C14H8O2, usually derived from anthracene or phthalic anhydride: used chiefly in the manufacture of anthraquinone dyes.
- a yellow crystalline solid used in the manufacture of dyes, esp anthraquinone dyes, which have excellent colour properties. Formula: C 6 H 4 (CO) 2 C 6 H 4