Dewar vessel
noun
a container with an evacuated space between two walls that are highly reflective, capable of maintaining its contents at a near-constant temperature over relatively long periods of time; thermos.
Origin of Dewar vessel
1900–05; named after Sir James Dewar, its inventor
Also called Dewar, Dewar flask.
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019