alkali vs pyrimidine

alkali and pyrimidine both are nouns.

Word	Noun	Adjective	Verb	Adverb
alkali	Yes	No	No	No
pyrimidine	Yes	No	No	No

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

alkali: any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water
pyrimidine: any of several basic compounds derived from pyrimidine

Other hyponyms of alkali include pyridine, purine, purine, glyoxaline, imidazole, iminazole, cyanuramide, melamine.

alkali (noun)	pyrimidine (noun)
any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water	a heterocyclic organic compound with a penetrating odor
a mixture of soluble salts found in arid soils and some bodies of water; detrimental to agriculture	any of several basic compounds derived from pyrimidine