What does tunnelling mean?
Tunnelling means digging a passage through earth, rock, or another obstacle, or travelling through a passage that already exists. It is commonly associated with major engineering projects, including underground railways, roads, and utility networks, where tunnelling may proceed beneath cities, rivers, or mountains. The word can also have a technical figurative use in computing: network tunnelling carries data through an encapsulated route, often to provide privacy or connect to a remote network. As a present participle, tunnelling describes an activity in progress, as in “workers are tunnelling beneath the river,” while its gerund use names the activity itself, as in “the tunnelling was delayed by unstable ground.” British English conventionally uses the double-l spelling tunnelling, whereas American English generally spells it tunneling. The word is practical and broadly understood, though in its engineering sense it most often refers specifically to excavation rather than the finished tunnel itself.
verb (present participle and gerund)To make a passage by digging underground or through an obstacle, or to pass through an existing tunnel. In technical contexts, it can also mean creating or using a concealed or encapsulated route through a network.
- Digging or excavating a passage underground or through rock, soil, or another obstacle.
- Passing or travelling through a tunnel.
- Creating or using a concealed route through a computer network, as in virtual private network technology.
"Engineers spent several months tunnelling through unstable rock beneath the river."
"The crew is tunnelling through granite on the eastern side of the mountain."
"The company recommends tunnelling the connection through a private VPN when employees use public networks."
From railway cuttings to private VPN connections, tunnelling describes making a hidden passage through a barrier.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Words that share this root
Related word forms
How tunnelling is actually used
The double-l spelling is conventional in British English, while American English usually uses the single-l spelling tunneling. As a gerund, tunnelling can name the activity rather than an action occurring at a particular moment.
Easily confused with tunnelling
Tunneling is the usual American spelling, whereas tunnelling with two l's is the conventional British spelling; the forms have the same meaning.