tunnel

noun

• 1an artificial underground passage, especially one built through a hill or under a building, road, or river: a road tunnel through the Pyrenees the Mersey tunnel [as modifier]:the tunnel mouth
• an underground passage dug by a burrowing animal.
• a passage in a sports stadium by which players enter or leave the field: he jogged off the field and into the tunnel

• 2short for wind tunnel.

• 3a long, half-cylindrical enclosure used to protect plants, made of clear plastic stretched over hoops: cover plants in rows with a cloche tunnel

verb (tunnels, tunnelling, tunnelled; US tunnels, tunneling, tunneled)

• 1 [no object, with adverbial of direction] dig or force a passage underground or through something:he tunnelled under the fence (tunnel one's way)the insect tunnels its way out of the plant

• 2 [no object] Physics (of a particle) pass through a potential barrier.