thermionic valve vs thermionic tube

thermionic valve and thermionic tube both are nouns.

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

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

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

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

thermionic valve (noun)	thermionic 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