Source : Webster's Revised Unabridged Dictionary (1913)

Agon \Ag"on\, n.; pl. {Agones}. [Gr. ?, fr. ? to lead.] (Gr.
   Antiq.)
   A contest for a prize at the public games.

Source : WordNet®

agon
     n : a festivity in ancient Greece at which competitors contended
         for prizes
     [also: {agones} (pl)]