Tūn'nel1, n.
n. [From tun. Cf. Fr. tonnelle, a semi-circular, wagon-headed vault, a tunnel-net, an arbor, from tonne, a tun. See TUN.] 1. A vessel with a broad mouth at one end, and a pipe or tube at the other, for conveying liquor into casks, bottles, or other vessels; a funnel. And one great chimney, whose long tunnel thence The smoke forth threw. Spenser.
- The opening of a chimney for the passage of smoke; a flue; a funnel.
- An artificial arch or passage 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.
- (Mining.) A level passage driven across the measures, or at right angles to the veins which its object is to reach; and thus distinguished from the drift or gangway, which is led along the vein when reached by the tunnel.