The term isomer comes from the Green ισο (iso-) which means equally or the same and μέρος (meros) which means is a part or sharing. This word is ambiguous in an energy context. It may refer to:
- Nuclear isomer: two different nucleus' with the same number of protons and neutrons, but they behave differently.
- Chemical isomer: two different molecules with the same number and type of atoms, but different configurations and properties.
- Oxford English Dictionary accessed January 29th, 2020 from https://www.oed.com/view/Entry/100097?redirectedFrom=isomer#eid