covering vs peridium

covering and peridium both are nouns.

Word	Noun	Adjective	Verb	Adverb
covering	Yes	No	No	No
peridium	Yes	No	No	No

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

covering (noun)	peridium (noun)
the act of protecting something by covering it	outer layer of the spore-bearing organ in many fungi
the work of applying something
the act of concealing the existence of something by obstructing the view of it
an artifact that covers something else (usually to protect or shelter or conceal it)
a natural object that covers or envelops