Diastereomer is a term used in chemistry to describe stereoisomers generated from the different spatial arrangement of atoms around one or more chiral centers in a molecule. Other synonyms for diastereomer include cis-trans isomer, enantiomer, epimer, anomers, and atropisomers. Each of these terms emphasizes a particular feature of the stereoisomers and is used in different contexts. For example, cis-trans isomers refer to isomers differing in the position of substituents on a double bond, while enantiomers refer to mirror-image isomers. Epimers differ in the configuration of only one chiral center, while anomers are epimers that differ primarily in the position of the substituent on a cyclic molecule. Atropisomers differ in the spatial orientation of aromatic rings connected by a single bond.