[ thur-muh s ]
/ ˈθɜr məs /


a vacuum bottle or similar container lined with an insulating material, such as polystyrene, to keep liquids hot or cold.


Origin of thermos

First recorded in 1905–10; formerly a trademark
Also called thermos bottle. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for thermos

British Dictionary definitions for thermos


Thermos flask

/ (ˈθɜːməs) /


trademark a type of stoppered vacuum flask used to preserve the temperature of its contentsSee also Dewar flask
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

Word Origin and History for thermos



trademark registered in Britain 1907, invented by Sir James Dewar (patented 1904 but not named then), from Greek thermos "hot" (see thermal). Dewar built the first one in 1892, but it was first manufactured commercially in Germany in 1904, when two glass blowers formed Thermos GmbH. Supposedly the company sponsored a contest to name the thing, and a Munich resident won with a submission of Thermos.

Online Etymology Dictionary, © 2010 Douglas Harper