1. a hollow cylinder used to hold or carry liquids, gases, or other substances
2. a container made of soft metal or plastic with a cap, used for holding paste-like substances
3. the London Underground railway system
Usage: British informal

1. to provide with tubes or enclose in a tube
2. to ride on an inflatable tube, especially down a river or snowy hill
Usage: informal

Examples

• Water flows through the metal tube.
• She squeezed toothpaste from the tube.
• We took the tube to central London.
• The old tube in the living room finally broke.
• They tubed the wiring through the wall.
• The kids went tubing down the snowy slope.
• The scientist examined the test tube carefully.
• Air passes through breathing tubes in the lungs.