Pronunciation: (tō'kē-ō"; Japn. tô'kyô),[key] —n. a seaport in and the capital of Japan, on Tokyo Bay: one of the world's largest cities; destructive earthquake and fire 1923; signing of the Japanese surrender document aboard the U.S.S. Missouri, September 2, 1945. 11,468,516. Also,To'ki•o".Formerly, Edo, Yeddo, Yedo.