vacuum flask
From Longman Dictionary of Contemporary EnglishRelated topics: Utensilsvacuum flaskˈvacuum ˌflask noun [countable] British English DFUa special container that keeps liquids hot or cold SYN thermosExamples from the Corpusvacuum flask• Keep the mixture in a vacuum flask for 6-8 hours.• Fairfax's steward has packed sandwiches for us and an ancient vacuum flask of tea.• What if we place Professor Summerlee upon the table, within the vacuum flask, in place of the cat?