retro

https://doi.org/10.1351/goldbook.R05370
  1. A prefix which indicates a shift by one position of all single and double bonds in a conjugated polyene system. It has been applied only to carotenoids and retinoids, e.g. retro-carotenoids, retro-retinoids.
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  2. A prefix which indicates the reverse sequence of a peptide.
Sources:
Blue Book Guide, p. 32 (https://doi.org/10.1351/pac199971071327)
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1363 (https://doi.org/10.1351/pac199567081307)
See also:
White Book, 2nd ed., p. 229 [Terms] [Book]
White Book, 2nd ed., p. 249 [Terms] [Book]
White Book, 2nd ed., p. 64 [Terms] [Book]