[{"Bold_text": "noun", "List Items": ["Chemistry.the relation of two or more compounds, radicals, or ions that are composed of the same kinds and numbers of atoms but differ from each other in structural arrangementstructural isomerism,as CH3OCH3and CH3CH2OH, or in the arrangement of their atoms in space and therefore in one or more properties.Compare optical isomerism optical isomerism, stereoisomerism .", "Also callednu·cle·ar i·som·er·ism[noo, -klee-er ahy-, som, -, uh, -riz-, uh, m, nyoo, -].Physics.the relation of two or more nuclides that have the same atomic number and mass number but different energy levels and half-lives.", "Chemistry, Physics.the phenomenon characterized by such a relation.", "the state or condition of being isomerous."]}]