tunnel

v. dig a tubular passage, create a tunnel

n. hollow underground passage; protected conveyance conduit through a mountain or under a body of water

A tunnel is an underground passage. The definition of what constitutes a tunnel is not universally agreed upon. However, in general tunnels are at least twice as long as they are wide. In addition, they should be completely enclosed on all sides, save for the openings at each end.A tunnel may be for pedestrians or cyclists, for general road traffic, for motor vehicles only, for rail traffic, or for a canal. Some are aqueducts, constructed purely for carrying water — for consumption, for  hydroelectric purposes or as sewers — while others carry other services such as  telecommunications cables. There are even tunnels designed as wildlife crossings for European badgers and other endangered species. Some secret tunnels have also been made as a method of entrance or escape from an area, such as the Cu Chi Tunnels or the tunnels connecting the Gaza Strip to Egypt.
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Noun
1. a passageway through or under something, usually underground (especially one for trains or cars); "the tunnel reduced congestion at that intersection"
(hypernym) passageway
(hyponym) catacomb
(classification) car, auto, automobile, machine, motorcar
2. a hole in the ground made by an animal for shelter
(synonym) burrow
(hypernym) hole, hollow
(hyponym) warren, rabbit warren
(derivation) burrow
Verb
1. move through by or as by digging; "burrow through the forest"
(synonym) burrow
(hypernym) dig, delve, cut into, turn over
(derivation) burrow
2. force a way through
(hypernym) penetrate, perforate

n. tunnel, hollow underground passage, protected conveyance conduit through a mountain or under a body of water

n. tunnel, hollow underground passage; protected conveyance conduit through a mountain or under a body of water