an electric railway operating below the surface of the ground (usually in a city)
2
n an electric railway operating below the surface of the ground (usually in a city) n an underground tunnel or passage enabling pedestrians to cross a road or railway
3
an electric railway operating below the surface of the ground (usually in a city) n
4
n conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases n electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope n a hollow cylindrical shape n (anatomy) any hollow cylindrical body structure n an electric railway operating below the surface of the ground (usually in a city) v provide with a tube or insert a tube into v convey in a tube v ride or float on an inflated tube v place or enclose in a tube