Tube (noun)

1. A long, cylindrical, hollow container, typically made of metal, glass, or plastic.
2. A pipe or channel for transporting a substance, especially a gas or liquid.
3. A type of transportation system consisting of enclosed trains running in underground tunnels.
4. A part of a device, such as a television, that is shaped like a tube.

Origin:

The word 'tube' originated from the latin word 'tubus' which means 'a hollow pipe or conduit.'.

Examples:

1. The toothpaste was packaged in a squeezable tube.
2. The blood is transported through tubes in the body called veins and arteries.
3. The London Underground, also known as the Tube, is one of the oldest metro systems in the world.
4. The television has a cathode ray tube that creates the image on the screen.
5. The air conditioning system uses tubes to circulate cool air throughout the building.