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definitions

inner tube

noun
  1. a doughnut-shaped, flexible rubber tube inflated inside a tire to bear the weight of a vehicle.

Origin of inner tube

First recorded in 1890–95
Also called tube.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for inner tube

inner tube

noun
  1. an inflatable rubber tube that fits inside a pneumatic tyre casing
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012