0 a long passage under or through the ground, especially one made by people:
The train went into the tunnel.
1 to dig a tunnel:
2 a long passage under or through the earth, esp. one made for vehicles:
3 to dig a tunnel:
Ten miners were trapped underground when the roof of the tunnel fell in.
It is not practicable to complete the tunnel before the end of the year.
A tunnel entrance was found within the precincts of the prison camp.
Termites tunnelled slowly in the dry sand, but diverted their tunnelling into the wet sand once it had been discovered.
Both are usually estimated using data derived by scanning tunneling microscopy from different surface specimens.
An infested tuber was defined as one with visible tunnelling damage, regardless of the presence or absence of larvae.
