Definition of "tube"

noun:
- Anything that is hollow and cylindrical in shape.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- An approximately cylindrical container, usually with a crimped end and a screw top, used to contain and dispense semi-liquid substances.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- 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.).
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- A wave which pitches forward when breaking, creating a hollow space inside.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- A television. Also, derisively, boob tube. British: telly.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
verb:
- To make or use tubes.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License