'amino-rich' is a modern English compound formed from the combining form 'amino-' and the adjective 'rich'. 'Amino-' comes from 'amine' (coined in the 19th century), where 'amine' was derived from 'ammonia' (via Modern Latin/French), and 'rich' comes from Old English 'rīċe' meaning 'powerful, abundant'.

'amino-' developed as a chemical combining form from the noun 'amine' (itself named in the 19th century from 'ammonia'); the combining form 'amino-' was attached to adjectives or nouns (e.g., amino acid) and later used in compounds such as 'amino-rich' to mean 'rich in amino content'.

Originally 'amino-' referred specifically to the presence of amine groups or derivatives of ammonia; in compounds like 'amino-rich' it now denotes abundance in amino groups or amino acids rather than just the presence of an amine functional group.