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.-the opening of a chimney for the passage of smoke; a flue; a funnel.-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.-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.-to form into a tunnel, or funnel, or to form like a tunnel; as, to tunnel fibrous plants into nests.-to catch in a tunnel net.-to make an opening, or a passageway, through or under; as, to tunnel a mountain; to tunnel a river.