magnetron vs thermionic tube

magnetron and thermionic tube both are nouns.

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

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

magnetron: a diode vacuum tube in which the flow of electrons from a central cathode to a cylindrical anode is controlled by crossed magnetic and electric fields; used mainly in microwave oscillators
thermionic tube: electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope

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

magnetron (noun)	thermionic tube (noun)
a diode vacuum tube in which the flow of electrons from a central cathode to a cylindrical anode is controlled by crossed magnetic and electric fields; used mainly in microwave oscillators	electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope