Source : Webster's Revised Unabridged Dictionary (1913)

Gorgon \Gor"gon\ (g[^o]r"g[o^]n), n. [L. Gorgo, -onis, Gr.
   Gorgw`, fr. gorgo`s terrible.]
   1. (Gr. Myth.) One of three fabled sisters, Stheno, Euryale,
      and Medusa, with snaky hair and of terrific aspect, the
      sight of whom turned the beholder to stone. The name is
      particularly given to Medusa.

   2. Anything very ugly or horrid. --Milton.

   3. (Zo["o]l.) The brindled gnu. See {Gnu}.

Gorgon \Gor"gon\, a.
   Like a Gorgon; very ugly or terrific; as, a Gorgon face.
   --Dryden.

Source : WordNet®

Gorgon
     n : (Greek mythology) any of three winged sister monsters and
         the mortal Medusa who had live snakes for hair; a glance
         at Medusa turned the beholder to stone