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tunnel

n. · v.
US //ˈtənəɫ// UK //tˈʌnəl// tun·nel
  1. 1 underground passage (n.)
    B1 Intermediate

    a long passage built under the ground, through a hill, or under a river for cars, trains, or people.

    an artificial underground or underwater passage, typically constructed for transportation or utility infrastructure.

    Example

    The train went through a long tunnel under the mountains.

    Example

    Engineers spent nearly a decade constructing the undersea tunnel to connect the two islands, overcoming significant geological challenges along the way.
  2. 2 animal burrow (n.)
    B2 Upper Intermediate

    a long hole in the ground made by an animal to live in or move through.

    a subterranean passage or burrow excavated by an animal for habitation or transit.

    Example

    The rabbit disappeared into a small tunnel near the edge of the field.

    Example

    The garden was riddled with complex tunnels created by moles, which had significantly damaged the root systems of the prize-winning roses.
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  1. 3 computing (n.)
    C1 Advanced Technical Computing

    a safe way to send data over the internet by hiding it inside another type of data.

    a communication protocol that allows for the movement of data from one network to another by encapsulating one protocol within another.

    Example

    He used a secure tunnel to access his office files from home.

    Example

    The network administrator established an SSH tunnel to bypass the restrictive firewall and manage the remote server securely.
  2. 4 to dig a passage (v.)
    B2 Upper Intermediate

    to dig a long hole under or through something.

    to excavate a tunnel through or under a physical barrier. Often used with 'through' or 'under'.

    Example

    The prisoners tried to tunnel under the wall to escape.

    Example

    The construction crew had to tunnel through solid granite to complete the new highway extension before the winter deadline.
  3. 5 physics (v.)
    C2 Proficiency Technical Science

    when a tiny particle passes through a barrier that it normally should not be able to cross.

    to undergo the quantum-mechanical phenomenon where a particle penetrates a potential energy barrier that it classically lacks the energy to surmount.

    Example

    In quantum physics, particles can sometimes tunnel through barriers.

    Example

    Quantum tunneling is a fundamental process in nuclear fusion, allowing protons to overcome their mutual electrostatic repulsion despite having insufficient kinetic energy.

Origin

From Middle French tonnelle (“net”) or tonel (“cask”), diminutive of Old French tonne (“cask”), a word of uncertain origin and affiliation. Related to Old English tunne (“tun; cask; barrel”). More at tun.

Idioms4 entries

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