Source : Webster's Revised Unabridged Dictionary (1913)

Hydroquinone \Hy`dro*qui"none\, n. [Hydro-, 2 + quinone.]
   (Chem.)
   A white crystalline substance, {C6H4(OH)2}, obtained by the
   reduction of quinone. It is a diacid phenol, resembling, and
   metameric with, pyrocatechin and resorcin. Called also
   {dihydroxy benzene}.