rectifying valve vs tube

rectifying valve and tube both are nouns.

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

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

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

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

rectifying valve (noun)	tube (noun)
a thermionic tube having two electrodes; used as a rectifier	conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases
	an electric railway operating below the surface of the ground (usually in a city)
	electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
	(anatomy) any hollow cylindrical body structure
	a hollow cylindrical shape

rectifying valve (verb)	tube (verb)
	place or enclose in a tube
	convey in a tube
	ride or float on an inflated tube
	provide with a tube or insert a tube into