vacuum flask
1
4.2
- noun
- /ˈvæk.juːm flæsk/
- The scientist used a vacuum flask to store liquid helium at a stable temperature.
Examples
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I poured my hot coffee into a vacuum flask to keep it warm during the hike.
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Its metal surface scorched and discolored, it stands upright in a vacuum flask, as if saluting.
Fiction book (1991) -
And then indeed how you would contain the filament, is it in a vacuum flask or is it in a, a gas or whatever.
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So in this box is some hot water, and in this vacuum flask is about a litre of liquid nitrogen.
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There is much confusion about thermal conductivity throughout this thread, and I think much of it comes from people's everyday experience with vacuum flasks, in which they understand that reducing the pressure in the cavity between the walls.
Blog text (18) -
To ensure her soup stayed hot, she packed it in a vacuum flask for the picnic.
Synonyms
1
2.5
A bottle that keeps drinks hot or cold for a long time
1
3.4
A container that keeps drinks hot or cold for a long time
1
3.7
A container with two walls and empty space between them that keeps drinks hot or cold
1
8.4
A container that keeps very cold liquids like liquid nitrogen from warming
How Insulating
1
4.2
1
3.4
Surface Forms
Morphology
The meaning is directly derivable from combining 'vacuum' (an empty space) with 'flask' (a container): a B1 learner who knows both words can infer it is a container that uses a vacuum to insulate liquids. This noun+noun compound follows a transparent compositional pattern common across languages, so the sense is predictable without prior exposure.
Etymology
The noun vacuum flask comes from a simple picture: a glass flask inside another, with a space that has almost no air called a vacuum between the walls. So, that empty space stops heat moving, and the vacuum flask keeps liquids 'hot' or 'cold' for a long time.