subway用得多于metro
The Tokyo subway is an integral part of the world's most extensive rapid transit system in a single metropolitan area, Greater Tokyo. While the subway system itself is largely within the city center, the lines extend far out via extensive through services onto suburban railway lines.
但是东京地下铁公司就用tokyo metro(这并非东京唯一的地铁,另一部分归东京都交通局所管)
Tokyo Metro (东京メトロ) is one of two rapid transit systems making up the Tokyo subway system, the other being Toei. It is the first most used subway system in the world in terms of annual passenger rides.