Synonyms of the word

underpass

• n. A road or a pedestrian passage in a tunnel that runs underneath a road or railroad.

subway

• n. (Canada, US, Scotland) An underground railway, especially for mass transit of people in urban areas.
• n. (US) A rapid transit system, regardless of the elevation of its right of way.
• n. (Britain) An underground walkway, tunnel for pedestrians (called pedestrian underpass in US).
• v. (intransitive, US, informal) To travel by underground railway.

tunnel

• n. An underground or underwater passage.
• n. A passage through or under some obstacle.
• n. A hole in the ground made by an animal, a burrow.
• n. (computing, networking) A wrapper for a protocol that cannot otherwise be used because it is unsupported,…
• n. A vessel with a broad mouth at one end, a pipe or tube at the other, for conveying liquor, fluids, etc…
• n. The opening of a chimney for the passage of smoke; a flue.
• n. (mining) A level passage driven across the measures, or at right angles to veins which it is desired to…
• v. (transitive) To make a tunnel through or under something, to burrow.
• v. (intransitive) To make a tunnel.