elytron vs wing case

elytron and wing case both are nouns.

Word	Noun	Adjective	Verb	Adverb
elytron	Yes	No	No	No
wing case	Yes	No	No	No

As nouns, elytron and wing case are synonyms defined as:

elytron and wing case: either of the horny front wings in beetles and some other insects which cover and protect the functional hind wings

elytron (noun)	wing case (noun)
either of the horny front wings in beetles and some other insects which cover and protect the functional hind wings	either of the horny front wings in beetles and some other insects which cover and protect the functional hind wings