A facility, comparable to a wind tunnel, in which an underwater component may be tested in a controlled flow of water. / A tunnel used to transport water.

A tunnel which allows workers to maintain pipes which transport steam between a central boiler and buildings to be heated or cooled, usually in a campus setting.

plural of steam tunnel

A test facility through which air is forced in a controlled manner so as to study the effects of flow around airfoils, aircraft, motor cars etc.

(idiomatic) A better situation after long hardship. / A vision of a bright light, surrounded by darkness, seen by a dying person

(neurology) form of repetitive stress injury caused by compression of the median nerve travelling through the carpal tunnel.

(business) The application of a rigorous testing regime to a new corporate idea, structure or project to see if it is viable and fit for purpose.

(rail transport) A railway station and junction in Monmouthshire, Wales, on the west side of the Severn Tunnel, which serves the village of Rogiet (OS grid ref ST4687).

plural of tunnel boring machine

(engineering) A large machine used to excavate tunnels with a circular cross section.