Tunnel

1. n. . A level passage driven across the measures, or at right angles to veins which it is desired to reach; — distinguished from the drift, or gangway, which is led along the vein when reached by the tunnel.
2. n. . A vessel with a broad mouth at one end, a pipe or tube at the other, for conveying liquor, fluids, etc., into casks, bottles, or other vessels; a funnel.
3. n. . The opening of a chimney for the passage of smoke; a flue; a funnel.
4. n. . An artificial passage or archway for conducting canals or railroads under elevated ground, for the formation of roads under rivers or canals, and the construction of sewers, drains, and the like.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.