/ ˈtʌnl; NAmE / noun , verb
■ noun
1.
a passage built underground, for example to allow a road or railway / railroad to go through a hill, under a river, etc. :
a railway / railroad tunnel
the Channel Tunnel
—see also wind tunnel
2.
an underground passage made by an animal
•
IDIOMS
see light noun
■ verb
( -ll- , NAmE also -l- ) [+ adv. / prep. ] to dig a tunnel under or through the ground :
[ v ]
The engineers had to tunnel through solid rock.
[ vn ]
The rescuers tunnelled their way in to the trapped miners.
••
WORD ORIGIN
late Middle English (in the senses tunnel-shaped net and flue of a chimney ): from Old French tonel , diminutive of tonne cask. The current noun senses date from the mid 18th cent.