thermionic vacuum tube vs vacuum tube

thermionic vacuum tube and vacuum tube both are nouns.

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

As nouns, thermionic vacuum tube and vacuum tube are synonyms defined as:

thermionic vacuum tube and vacuum tube: electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope

Other synonyms of thermionic vacuum tube include electron tube, thermionic tube, thermionic valve, tube.

thermionic vacuum tube (noun)	vacuum tube (noun)
electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope	electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope