rectifying valve vs diode

rectifying valve and diode both are nouns.

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

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

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

Other synonyms of rectifying valve include rectifying tube.

rectifying valve (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