- an envelope of enclosed air around part of a machine, as for checking the transmission of heat.
- British. life jacket.
Origin of air jacket
First recorded in 1905–10
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for air jacket
A is the calorimetric tube, B the air-jacket and L the gauge.
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