tube Noun Anything that is hollow and cylindrical in shape.
tube Noun An approximately cylindrical container, usually with a crimped end and a screw top, used to contain and dispense semi-liquid substances.
tube Noun The London Underground railway system, originally referred to the lower level lines that ran in tubular tunnels as opposed to the higher ones which ran in rectangular section tunnels. (Often "the tube".)
tube Noun A tin can containing beer (or other beverage?)
tube Noun A wave which pitches forward when breaking, creating a hollow space inside.
tube Noun A television. Also, derisively, boob tube. British: telly