ambo

A prefix used to indicate that a molecule with two (or more) chiral elements is present as a mixture of the two racemic diastereoisomers in unspecified proportions. For example, the dipeptide formed from l-alanine and dl-leucine is l-alanyl-ambo-leucine.
Source:
PAC, 1996, 68, 2193 (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2198
See also:
PAC, 1984, 56, 595 (Nomenclature and symbolism for amino acids and peptides (Recommendations 1983)) on page 595
PAC, 1982, 54, 1507 (Nomenclature of tocopherols and related compounds) on page 1507