Roman hyacinth vs hyacinth

Roman hyacinth and hyacinth both are nouns.

Word	Noun	Adjective	Verb	Adverb
Roman hyacinth	Yes	No	No	No
hyacinth	Yes	No	No	No

As nouns, hyacinth is a hypernym of Roman hyacinth; that is, hyacinth is a word with a broader meaning than Roman hyacinth:

Roman hyacinth: hyacinth with loosely flowered spikes, several growing from one bulb
hyacinth: any of numerous bulbous perennial herbs

Roman hyacinth (noun)	hyacinth (noun)
hyacinth with loosely flowered spikes, several growing from one bulb	any of numerous bulbous perennial herbs
	a red transparent variety of zircon used as a gemstone