diode vs thermionic vacuum tube

diode and thermionic vacuum tube both are nouns.

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

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

diode: a thermionic tube having two electrodes; used as a rectifier
thermionic vacuum tube: electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope

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

diode (noun)	thermionic vacuum tube (noun)
a semiconductor that consists of a p-n junction	electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
a thermionic tube having two electrodes; used as a rectifier