sherbert vs frozen dessert

sherbert and frozen dessert both are nouns.

Word	Noun	Adjective	Verb	Adverb
sherbert	Yes	No	No	No
frozen dessert	Yes	No	No	No

As nouns, frozen dessert is a hypernym of sherbert; that is, frozen dessert is a word with a broader meaning than sherbert:

sherbert: a frozen dessert made primarily of fruit juice and sugar, but also containing milk or egg-white or gelatin
frozen dessert: any of various desserts prepared by freezing

sherbert (noun)	frozen dessert (noun)
a frozen dessert made primarily of fruit juice and sugar, but also containing milk or egg-white or gelatin	any of various desserts prepared by freezing