The Collaborative International Dictionary of English v.0.48:
Agon \Ag"on\, n.; pl. Agones. [Gr. ?, fr. ? to lead.] (Gr. Antiq.) A contest for a prize at the public games. [1913 Webster]WordNet (r) 3.0 (2006):
agon n 1: a festivity in ancient Greece at which competitors contended for prizes