rectifying tube vs diode

rectifying tube and diode both are nouns.

Word	Noun	Adjective	Verb	Adverb
rectifying tube	Yes	No	No	No
diode	Yes	No	No	No

As nouns, rectifying tube and diode are synonyms defined as:

rectifying tube and diode: a thermionic tube having two electrodes; used as a rectifier

Other synonyms of rectifying tube include rectifying valve.

rectifying tube (noun)	diode (noun)
a thermionic tube having two electrodes; used as a rectifier	a semiconductor that consists of a p-n junction
	a thermionic tube having two electrodes; used as a rectifier