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