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. 2019
British Dictionary definitions for inner tube
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