'diastereomeric' originates from New Latin/Greek, specifically the word 'diastereomer', where 'dia-' meant 'apart', 'stereo-' meant 'solid' (referring to spatial arrangement), and 'isomer' comes from Greek 'isomeros' meaning 'equal part'.

'diastereomeric' entered chemical usage in the 19th century from the noun 'diastereomer' (formed from Greek elements), and the adjectival suffix '-ic' was later attached to form the modern adjective 'diastereomeric'.

Initially, it meant 'relating to species of stereoisomers that are not mirror images'; this technical meaning has been retained in modern chemistry.