1. a former town on the Bosporus (now part of Istanbul); site of the Council of Chalcedon • Syn: Kadikoy • Instance Hypernyms: town • Part Holonyms: Istanbul, Stambul, Stamboul, Constantinople 2. the fourth ecumenical council in 451 which defined the two natures (human and divine) of Christ • Syn: Council of Chalcedon • Hypernyms: ecumenical council