tunnel

1 of 3

noun (1)

tun·​nel ˈtə-nᵊl 

1

a

: a covered passageway

specifically : a horizontal passageway through or under an obstruction

b

: a subterranean gallery (as in a mine)

c

: burrow

2

: a hollow conduit or recess : tube, well

tunnellike

ˈtə-nᵊl-ˌ(l)īk 

adjective

tunnel

2 of 3

verb

tunneled or tunnelled; tunneling or tunnelling

ˈtən-liŋ, 

ˈtə-nᵊl-iŋ 

intransitive verb

1

: to make or use a tunnel

2

physics : to pass through a potential barrier

electrons tunneling through an insulator between semiconductors

transitive verb

: to make a tunnel or similar opening through or under

also : to make (one's way) by or as if by making a tunnel

tunneler

ˈtən-lər, 

ˈtə-nᵊl-ər 

noun

tunneler

3 of 3

noun (2)

tun·​nel·​er

variants or tunneller

-n(ᵊ)lə(r)

plural -s

: one that tunnels: such as

a

: a workman employed in excavating a tunnel

b

: a machine used in tunneling (as in mining to cut a drift)

Examples of tunnel in a Sentence

Noun (1)

The train goes through a tunnel in the mountain.

The moles dug tunnels in the yard.

Verb

Workers are tunneling through the hill.

Insects had tunneled into the tree.

Recent Examples on the Web

Noun

This changes the alignment of the two ferromagnetic layers, which alters how easily electrons can tunnel through the insulating barrier (a quantum phenomenon known as tunnel magnetoresistance) and changes the sensor’s electrical resistance. — ArsTechnica, 5 Oct. 2026

Traditional secure email gateways and web proxies rely on inspecting SMTP traffic or forcing browser sessions through corporate network tunnels. — Firas Azmeh, Forbes.com, 5 Oct. 2026

Verb

Scanning tunneling microscopy probes the material’s surface, so the researchers cannot yet prove that the same PDW exists throughout the interior. — Rupendra Brahambhatt, Interesting Engineering, 4 Oct. 2026

Our work explained how making a minor modification to a reacting molecule – switching the hydrogen to deuterium – could increase the size of the energy barrier and stop tunneling. — Sophya Garashchuk, The Conversation, 1 Oct. 2026

Word History

Etymology

Noun (1)

Middle English tonel cask, tun, from Anglo-French, from tone tun

First Known Use

Noun (1)

1508, in the meaning defined at sense 2

Verb

1795, in the meaning defined at intransitive sense 1

Phrases Containing tunnel

• a light at the end of the tunnel
• carpal tunnel syndrome
• high tunnel
• tunnel vision
• wind tunnel

Rhymes for tunnel

• bunnell
• funnel
• fentanyl
• multifunctional

Kids Definition

tunnel

1 of 2 noun

tun·​nel ˈtən-ᵊl 

: a passage under the ground

tunnellike

-ᵊl-ˌ(l)īk 

adjective

tunnel

2 of 2 verb

tunneled or tunnelled; tunneling or tunnelling

ˈtən-liŋ, 

-ᵊl-iŋ

: to make a tunnel

Medical Definition

tunnel

noun

tun·​nel ˈtən-ᵊl 

: a bodily channel see carpal tunnel