cystine vs amino acid

cystine and amino acid both are nouns.

Word	Noun	Adjective	Verb	Adverb
cystine	Yes	No	No	No
amino acid	Yes	No	No	No

As nouns, amino acid is a hypernym of cystine; that is, amino acid is a word with a broader meaning than cystine:

cystine: a crystalline amino acid found in proteins (especially keratin); discovered in bladder stones
amino acid: organic compounds containing an amino group and a carboxylic acid group

Other hypernyms of cystine include aminoalkanoic acid.

cystine (noun)	amino acid (noun)
a crystalline amino acid found in proteins (especially keratin); discovered in bladder stones	organic compounds containing an amino group and a carboxylic acid group