eosin vs fluorescent dye

eosin and fluorescent dye both are nouns.

Word	Noun	Adjective	Verb	Adverb
eosin	Yes	No	No	No
fluorescent dye	Yes	No	No	No

As nouns, fluorescent dye is a hypernym of eosin; that is, fluorescent dye is a word with a broader meaning than eosin:

eosin: a red fluorescent dye resulting from the action of bromine on fluorescein; used in cosmetics and as a biological stain for studying cell structures
fluorescent dye: a yellow dye that is visible even when highly diluted; used as an absorption indicator when silver nitrate solution is added to sodium chloride in order to precipitate silver chloride (turns pink when no chloride ions are left in solution and negative fluorescein ions are then absorbed)

Other hypernyms of eosin include fluorescein, fluoresceine, resorcinolphthalein.

eosin (noun)	fluorescent dye (noun)
a red fluorescent dye resulting from the action of bromine on fluorescein; used in cosmetics and as a biological stain for studying cell structures	a yellow dye that is visible even when highly diluted; used as an absorption indicator when silver nitrate solution is added to sodium chloride in order to precipitate silver chloride (turns pink when no chloride ions are left in solution and negative fluorescein ions are then absorbed)