polypeptides

https://doi.org/10.1351/goldbook.P04749
peptides containing ten or more amino acid residues.
Sources:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1359 (https://doi.org/10.1351/pac199567081307)
White Book, 2nd ed., p. 48 (https://www.qmul.ac.uk/sbcs/iupac/bibliog/white.html)