1. underground or underwater passages, typically for transportation

1. digs or bores through something to create a passage
2. moves through something as if through a tunnel

Examples

• The subway tunnels run deep beneath the city.
• Engineers built tunnels through the mountain for the highway.
• The mole tunnels through the soft earth in search of food.
• She tunnels under the fence to escape the yard.
• The train speeds through the dark tunnels.
• Workers are digging new tunnels for the metro expansion.
• The rabbit tunnels into the hillside to make its burrow.