武藏 (Wǔcáng / Japanese: Musashi) is the old name of the province covering modern Tokyo, Saitama and parts of Kanagawa — the same name that famous swordsman
宫本武藏 (Gōngběn Wǔcáng, Miyamoto Musashi) carries.
台 (tái, Japanese: -dai) is a common Japanese place-name suffix meaning 'plateau / heights'. So Musashidai = 'Musashi Heights'.