WordNet (r) 3.0 (2006):
Chalcedon n 1: a former town on the Bosporus (now part of Istanbul); site of the Council of Chalcedon [syn: Chalcedon, Kadikoy] 2: the fourth ecumenical council in 451 which defined the two natures (human and divine) of Christ [syn: Chalcedon, Council of Chalcedon]