dust cover vs protective cover

dust cover and protective cover both are nouns.

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

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

dust cover: a removable plastic protective covering for a piece of equipment
protective cover: a covering that is intend to protect from damage or injury

Other hypernyms of dust cover include protection, protective covering.

dust cover (noun)	protective cover (noun)
a removable plastic protective covering for a piece of equipment	a covering that is intend to protect from damage or injury
a large piece of cloth used to cover furniture that is not in use for a long period
a paper jacket for a book; a jacket on which promotional information is usually printed