Where does “enantiomerical” come from?

enantiomerical (English) comes from English enantiomer, from English -mer, from Ancient Greek μέρος, from Proto-Hellenic *(h)méros.

Ancestry of “enantiomerical”, step by step

StepLanguageWordMeaning
1EnglishenantiomerOne of a pair of stereoisomers that is the mirror...
2English-mer
3Ancient Greekμέροςpart, component, region; share, portion; one's...
4Proto-Hellenic*(h)méros
Every word from Proto-Hellenic *(h)mérosEvery word from Ancient Greek μέροςEvery word from English -mer