Oligopeptide. Definition. noun, plural: oligopeptides. A peptide comprised of relatively small number of amino acid residues (i.e. about two to forty). Supplement. Oligopeptides, which are sometimes simply referred to as peptides, are short chains of amino acid monomers linked via peptide bonds.The term oligopeptide is used to refer to a peptide with fewer members of amino acids as opposed to a polypeptide, which is a peptide comprised of several amino acid residues. peptide comprised of relatively small number of amino acid residues (i.e. about two to forty). Supplement. Oligopeptides, which are sometimes simply referred to as peptides, are short chains of amino acid monomers linked via peptide bonds.