1 文書を見つけるための辞書。

• tube, subway system, subway, metro, underground
• サブウェー, 地下鉄, 地下鉄道, メトロ
• an electric railway operating below the surface of the ground (usually in a city); "in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'"
• 地下を走る電車（通常都市で）