vacuum flask
B1Neutral, slightly formal. 'Thermos' is the more common informal term.
Definition
Meaning
A container with double walls enclosing a vacuum, used to keep liquids hot or cold for an extended period.
Any double-walled, insulated container, often made of metal or plastic, designed for thermal retention. Can refer by metonymy to similar insulated containers like travel mugs.
Linguistics
Semantic Notes
The term is generic and descriptive, though often capitalised as 'Vacuum Flask' as a historical reference to the original Dewar flask. It denotes the scientific principle (vacuum insulation) rather than a specific brand.
Dialectal Variation
British vs American Usage
Differences
In British English, 'vacuum flask' is the standard generic term. In American English, the brand name 'Thermos' is overwhelmingly the generic term; 'vacuum flask' sounds technical or old-fashioned.
Connotations
UK: Practical, scientific. US: Technical, possibly archaic.
Frequency
High frequency in UK English; low frequency in everyday US English, where 'thermos' dominates.
Vocabulary
Collocations
Grammar
Valency Patterns
fill a vacuum flask with [liquid]take a vacuum flask to [place/event]keep [liquid] hot/cold in a vacuum flaskVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[None directly associated]”
Usage
Context Usage
Business
Rare, except in manufacturing or retail contexts for outdoor/leisure products.
Academic
Used in physics and engineering contexts to describe the principle of vacuum insulation.
Everyday
Common in UK: 'I'll make some tea for the journey in the vacuum flask.'
Technical
Precise term for a vessel using a vacuum between walls as thermal insulation.
Examples
By Part of Speech
adjective
British English
- vacuum-flask technology
- a vacuum-flask design
American English
- vacuum-flask principle (technical)
Examples
By CEFR Level
- I have a vacuum flask for my tea.
- The soup is in the vacuum flask.
- She packed a vacuum flask of hot chocolate for the winter hike.
- A good vacuum flask can keep drinks hot for over 12 hours.
- The efficiency of a vacuum flask relies on the near-total absence of matter between its walls to minimise heat transfer.
- He criticised the cheap design, noting that the vacuum flask's seal was already failing.
- The invention of the vacuum flask by Sir James Dewar revolutionised the portable storage of liquefied gases and beverages alike.
- Modern iterations of the vacuum flask often incorporate additional layers of reflective coating to further impede radiative heat loss.
Learning
Memory Aids
Mnemonic
Think of the word 'vacuum' – it means empty space. A vacuum flask has an empty space between its walls to stop heat from escaping.
Conceptual Metaphor
A PORTABLE CLIMATE: The flask creates a miniature, stable thermal environment isolated from the outside world.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid калька 'вакуумная колба' in everyday contexts; it's overly technical. In the UK, use 'vacuum flask' or 'flask'; in the US, use 'thermos'. The Russian 'термос' maps directly to the US generic 'thermos'.
Common Mistakes
- Misspelling as 'vacume flask'. Using 'vacuum flask' in casual US conversation where 'thermos' is expected.
Practice
Quiz
In which variety of English is 'vacuum flask' the most common generic term for an insulated container?
FAQ
Frequently Asked Questions
Yes, in terms of the object. 'Thermos' is a trademark that became a generic term, especially in American English. 'Vacuum flask' is the descriptive, non-branded term, common in British English.
Yes. The vacuum insulation slows down heat transfer in both directions, so it can keep cold drinks cold and hot drinks hot.
A vacuum contains almost no molecules, which prevents heat from being transferred by conduction or convection. This is what provides the insulation.
It is neutral but leans towards the formal/descriptive. In everyday casual conversation in many regions, people are more likely to use the brand name 'thermos' or simply 'flask' (in the UK context).