'stereoisomer' originates from Greek-derived elements, specifically 'stereo-' (from Greek 'stereos') and 'isomer' (from Greek 'isomerēs'), where 'stereos' meant 'solid, three-dimensional' and 'isomerēs' is based on 'isos' meaning 'equal' and 'meros' meaning 'part'.

'stereoisomer' was formed in English by combining the prefix 'stereo-' (borrowed via scientific New Latin/Greek formation) with 'isomer' (from Greek roots) in the late 19th to early 20th century as stereochemistry developed; this compound formation produced the modern English term 'stereoisomer'.

Initially used to denote isomers differing in spatial arrangement in early stereochemistry literature, it has retained that core meaning and is now the standard term for isomers that differ only in three-dimensional arrangement.