地下鉄は英語で
subway

英語の定義

地下鉄
1. n. (railroads) rapid transit, metro, (AmE) subway, (BrE) underground

subway
1. n. (North America, Scotland) An underground railway, especially for mass transit of people in urban areas. (c, en, Rail transportation)
2. n. (US) A rapid transit system, regardless of the elevation of its right of way.
3. n. (British) An underground walkway, tunnel for pedestrians (called pedestrian underpass in US).
4. n. An underground route for pipes, sewers, etc.
5. v. (intransitive, US, informal) To travel by underground railway.