kelp vs tang

kelp and tang both are nouns.

Word	Noun	Adjective	Verb	Adverb
kelp	Yes	No	No	No
tang	Yes	No	No	No

As nouns, tang is a hyponym of kelp; that is, tang is a word with a more specific, narrower meaning than kelp:

Other hyponyms of kelp include sea tangle.

kelp (noun)	tang (noun)
large brown seaweeds having fluted leathery fronds	any of various kelps especially of the genus Laminaria
	any of various coarse seaweeds
	brown algae seaweed with serrated edges
	a common rockweed used in preparing kelp and as manure
	a tart spicy quality
	the taste experience when a savoury condiment is taken into the mouth