The Collaborative International Dictionary of English v.0.48:

Quinone \Qui"none\, n. [Quinine + ketone.] (Chem.)
   A crystalline substance, C6H4O2 (called also
   benzoketone), first obtained by the oxidation of quinic
   acid and regarded as a double ketone; also, by extension, any
   one of the series of which quinone proper is the type.
   [Written also chinone, kinone.]
   [1913 Webster]