cowling vs protective cover

cowling and protective cover both are nouns.

Word	Noun	Adjective	Verb	Adverb
cowling	Yes	No	No	No
protective cover	Yes	No	No	No

As nouns, protective cover is a hypernym of cowling; that is, protective cover is a word with a broader meaning than cowling:

cowling: protective covering consisting of a metal part that covers the engine
protective cover: a covering that is intend to protect from damage or injury

Other hypernyms of cowling include protection, protective covering.

cowling (noun)	protective cover (noun)
protective covering consisting of a metal part that covers the engine	a covering that is intend to protect from damage or injury