A tube is hollow cylindrical shape.

A collapsible tube is used as package for e.g. toothpaste, skin care products, shoe-polish and some foods, e.g. cheese. As a gimmick there are also tubes with alcoholic and non-alcoholic beverages.

For related terms see:

• Cathode ray tube / Electron tube
• Inner tube
• Test tube
• Vacuum tube (or Thermionic valve)
• London Underground ("The Tube")
• Tube computer bus
• TUBE (Japanese pops musician)

In surfing, the inside of a hollow wave is known as a tube.