Definition of peptides

Amides derived from two or more amino carboxylic acid molecules (the same or different) by formation of a covalent bond from the carbonyl carbon of one to the nitrogen atom of another with formal loss of water. The term is usually applied to structures formed from -amino acids, but it includes those derived from any amino carboxylic acid. BNRD, Rule 3AA-11 (p. 48). See also proteins, retro. Cf. carboxylic acids.

(R may be any organyl group, commonly but not necessarily one found in natural amino acids)