thermos vs vacuum bottle

thermos and vacuum bottle both are nouns.

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

As nouns, vacuum bottle is a hypernym of thermos; that is, vacuum bottle is a word with a broader meaning than thermos:

thermos: vacuum flask that preserves temperature of hot or cold drinks
vacuum bottle: flask with double walls separated by vacuum; used to maintain substances at high or low temperatures

Other hypernyms of thermos include vacuum flask.

thermos (noun)	vacuum bottle (noun)
vacuum flask that preserves temperature of hot or cold drinks	flask with double walls separated by vacuum; used to maintain substances at high or low temperatures