1. An underground or underwater passage.
2. A passage through or under a barrier such as a mountain.
3. A tube-shaped structure.
v. tun·neled, tun·nel·ing, tun·nels or tun·nelled or tun·nel·ling
1. To make a tunnel through or under: tunneling the granite.
2. To produce, shape, or dig in the form of a tunnel: tunnel a passageway out of prison.
To make a tunnel.
[Middle English tonel, barrel, tubular net, from Old French tonnel, diminutive of tonne, tun, possibly of Celtic origin.]
tunnel·er, tunnel·ler n.
(click for a larger image)tunnel
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.