plethora vs redundancy

plethora and redundancy both are nouns.

Word	Noun	Adjective	Verb	Adverb
plethora	Yes	No	No	No
redundancy	Yes	No	No	No

As nouns, redundancy is a hyponym of plethora; that is, redundancy is a word with a more specific, narrower meaning than plethora:

Other hyponyms of plethora include redundance.

plethora (noun)	redundancy (noun)
extreme excess	repetition of an act needlessly
	the attribute of being superfluous and unneeded
	(electronics) a system design that duplicates components to provide alternatives in case one component fails
	repetition of messages to reduce the probability of errors in transmission