™ / ˈθɜːməs; NAmE ˈθɜːrməs/ ( BrE also ˈThermos flask ) ( NAmE also ˈThermos bottle ) noun
a particular kind of vacuum flask (= a container like a bottle with double walls with a vacuum between them, used for keeping liquids hot or cold)
—compare flask
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WORD ORIGIN
early 20th cent.: from Greek , literally hot .