isomerism
noun
isom·er·ism ī-ˈsä-mə-ˌri-zəm 
1
: the relationship of two or more chemical species that are isomers
2
: the relation of two or more nuclides with the same mass numbers and atomic numbers but different energy states and rates of radioactive decay
Word History
First Known Use
1838, in the meaning defined at sense 1
Medical Definition
isomerism
noun
isom·er·ism ī-ˈsäm-ə-ˌriz-əm
1
: the relation of two or more chemical species that are isomers
2
: the relation of two or more nuclides with the same mass numbers and atomic numbers but different energy states and rates of radioactive decay