vacuum flask vs vacuum bottle

vacuum flask and vacuum bottle both are nouns.

Word	Noun	Adjective	Verb	Adverb
vacuum flask	Yes	No	No	No
vacuum bottle	Yes	No	No	No

As nouns, vacuum flask and vacuum bottle are synonyms defined as:

vacuum flask and vacuum bottle: flask with double walls separated by vacuum; used to maintain substances at high or low temperatures

vacuum flask (noun)	vacuum bottle (noun)
flask with double walls separated by vacuum; used to maintain substances at high or low temperatures	flask with double walls separated by vacuum; used to maintain substances at high or low temperatures