The Collaborative International Dictionary of English v.0.48:

Amphictyony \Am*phic"ty*o*ny\, n.; pl. Amphictyonies. [Gr. ?.]
   (Grecian Hist.)
   A league of states of ancient Greece; esp. the celebrated
   confederation known as the Amphictyonic Council. Its object
   was to maintain the common interests of Greece.
   [1913 Webster]

WordNet (r) 3.0 (2006):

amphictyony
    n 1: an association of neighboring states or tribes in ancient
         Greece; established originally to defend a common religious
         center