in reference to one of several ancient Greek confederations of neighboring states, 1753, probably via French, from Greek amphiktionikos, from amphiktiones "neighbors," literally "they that dwell round about," from amphi "on both sides, all around" (from PIE root *ambhi- "around") + second element related to ktizein "to create, found," ktoina "habitation, township," from PIE *kti-, metathesized form of root *tkei- "to settle, dwell, be home."
The most famous was that of Delphi. Madison and other U.S. Founders devoted close study to it. Shaftesbury has amphictyonian (1711).