klystron vs vacuum tube

klystron and vacuum tube both are nouns.

Word	Noun	Adjective	Verb	Adverb
klystron	Yes	No	No	No
vacuum tube	Yes	No	No	No

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

klystron: an electron tube used to generate or amplify electromagnetic radiation in the microwave region by velocity modulation
vacuum tube: electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope

Other hypernyms of klystron include electron tube, thermionic tube, thermionic vacuum tube, thermionic valve, tube.

klystron (noun)	vacuum tube (noun)
an electron tube used to generate or amplify electromagnetic radiation in the microwave region by velocity modulation	electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope