amine vs monoamine

amine and monoamine both are nouns.

Word	Noun	Adjective	Verb	Adverb
amine	Yes	No	No	No
monoamine	Yes	No	No	No

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

amine: a compound derived from ammonia by replacing hydrogen atoms by univalent hydrocarbon radicals
monoamine: a molecule containing one amine group (especially one that is a neurotransmitter)

Other hyponyms of amine include histamine, aminobenzine, aniline, aniline oil, phenylamine, enamine, ptomain, ptomaine.

amine (noun)	monoamine (noun)
a compound derived from ammonia by replacing hydrogen atoms by univalent hydrocarbon radicals	a molecule containing one amine group (especially one that is a neurotransmitter)