gorgonian vs red coral

gorgonian and red coral both are nouns.

Word	Noun	Adjective	Verb	Adverb
gorgonian	Yes	No	No	No
red coral	Yes	No	No	No

As nouns, red coral is a hyponym of gorgonian; that is, red coral is a word with a more specific, narrower meaning than gorgonian:

gorgonian: corals having a horny or calcareous branching skeleton
red coral: corals of especially the Mediterranean having pink or red color used for ornaments and jewelry

Other hyponyms of gorgonian include sea feather, sea fan.

gorgonian (noun)	red coral (noun)
corals having a horny or calcareous branching skeleton	corals of especially the Mediterranean having pink or red color used for ornaments and jewelry
	the hard stony skeleton of a Mediterranean coral that has a delicate red or pink color and is used for jewelry