Pronunciation: (tun'l),[key] —n., v.,-neled, -nel•ing or (esp. Brit.)-nelled, -nel•ling.
—n. 1. an underground passage.
2. a passageway, as for trains or automobiles, through or under an obstruction, as a city, mountain, river, harbor, or the like.
3. an approximately horizontal gallery or corridor in a mine.
4. the burrow of an animal.
5. Dial.a funnel.
—v.t. 1. to construct a passageway through or under: to tunnel a mountain. 2. to make or excavate (a tunnel or underground passage): to tunnel a passage under a river. 3. to move or proceed by or as if by boring a tunnel: The river tunneled its way through the mountain. 4. to pierce or hollow out, as with tunnels.
—v.i. to make a tunnel or tunnels: to tunnel through the Alps.