a hollow cylinder or pipe of metal, glass, rubber, etc., usu. long in proportion to its diameter, used for conveying fluids, etc.; a tube.

a cylindrical, circular, inflatable casing, fitted, inside a tyre, to the wheel of a vehicle, for smooth movement and carrying load.

a small, collapsible, cylinder of metal or plastic sealed at one end and having a capped opening at the other from which paint, toothpaste or some other semifluid substance may be squeezed.