Subway
Part of speech: noun
Definition: An underground railway, especially for mass transit of people in urban areas. A rapid transit system, regardless of the elevation of its right of way. underground walkway, tunnel for pedestrians (called pedestrian underpass in US).
Example sentence: If I ever have to stop taking the subway, I'm gonna have a heart attack.
Underpass
Part of speech: noun
Definition: A road or a pedestrian passage in a tunnel that runs underneath a road or railroad.