A thermos is the metal bottle with a screw top that keeps your tea hot for hours. You fill it at seven in the morning and at two in the afternoon, on a cold building site, it is still steaming.
The trick is a double wall with a vacuum between the layers, so heat cannot cross — which means a thermos keeps cold drinks cold just as well as it keeps hot drinks hot. In British English the everyday word is flask, or vacuum flask: 'I'll put the coffee in a flask.' Thermos began as a trademark and slid into ordinary use, so it takes a small t and a normal plural, thermoses. You will also see it as the first half of a compound: thermos flask, thermos mug. Do not mix it up with a hip flask, which holds whisky and keeps nothing warm.
1nounthermosA container with double walls and a vacuum between them, used to keep drinks or food hot or cold.
“He unscrewed the thermos and poured coffee into the lid.”
Patterna thermos of + noun (coffee, soup) · fill the thermos · thermos flask
synonyms: flask, vacuum flask
thermos is a container.
Also accepted in games: flask
THERMOS → hot tea at the top of a cold mountain
At the top of a cold mountain you open the bottle, and steam rises from tea that was made at breakfast: a thermos.
Thermos was a brand before it was a word. The company took its name from Ancient Greek θερμός, 'warm' — the same root you can see in thermometer and thermal — and sold so many vacuum flasks that people began calling every one of them a thermos, whoever had made it. The trademark dissolved into the language.
Proto-Indo-European
*gʷʰer-
Ancient Greek
θερμός — warm
English, today
thermos
Genericization of the trademark Thermos, from Ancient Greek θερμός (“warm”). Possibly related to English a doublet of warm.
Etymology from Wiktionary, CC BY-SA
Practised in In the Kitchen, A Man Called Ove, Containers & Packaging
First appears in chapter 15 of A Man Called Ove.
Practise this word