cover slip vs plate glass

cover slip and plate glass both are nouns.

Word	Noun	Adjective	Verb	Adverb
cover slip	Yes	No	No	No
plate glass	Yes	No	No	No

As nouns, plate glass is a hypernym of cover slip; that is, plate glass is a word with a broader meaning than cover slip:

cover slip: a small and very thin piece of glass used to cover the specimen on a microscope slide
plate glass: glass formed into large thin sheets

Other hypernyms of cover slip include sheet glass.

cover slip (noun)	plate glass (noun)
a small and very thin piece of glass used to cover the specimen on a microscope slide	glass formed into large thin sheets