covering vs eggshell

covering and eggshell both are nouns.

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

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

covering (noun)	eggshell (noun)
the act of protecting something by covering it	the exterior covering of a bird's egg
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