It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ventilation …

Dec 19, 2025 · Tunnels and underground excavations, horizontal underground passageway produced by excavation or occasionally by nature’s action in dissolving a soluble rock. Tunnels have many …

TUNNEL definition: an underground passage. See examples of tunnel used in a sentence.

TUNNEL meaning: 1. a long passage under or through the ground, especially one made by people: 2. the long passage…. Learn more.

In general, tunnels are at least twice as long as they are wide and are completely enclosed on all sides, save for the openings at each end. A tunnel may be used by pedestrians, cyclists, motor vehicles, or …

Jul 31, 2025 · A tunnel is a horizontal or slightly inclined underground passage. Learn about the definition, components, and types of tunnels, including hydraulic and traffic tunnels.

Definition of tunnel noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

A tunnel is a long passage which has been made under the ground, usually through a hill or under the sea. Boston drivers love the tunnel.

Tunnel definition: A passage through or under a barrier such as a mountain.

Today, engineers know that there are three basic steps to building a stable tunnel. The first step is excavation: engineers dig through the earth with a reliable tool or technique. The second...