isomer

American  

[ahy-suh-mer] / ˈaɪ sə mər /

noun

1. Chemistry. a compound displaying isomerism with one or more other compounds.

2. Also called nuclear isomer.  Physics. a nuclide that exhibits isomerism with one or more other nuclides.

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isomer British  

/ ˌaɪsəˈmɛrɪk, ˈaɪsəmə /

noun

1. chem a compound that exhibits isomerism with one or more other compounds

2. physics a nuclide that exhibits isomerism with one or more other nuclides

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isomer Scientific  

/ ī′sə-mər /

1. Chemistry Any of two or more substances that have the same molecular formula but differ in their connectivity or spatial arrangement of atoms, or in their topology in macromolecules.

2. Physics Any of two or more nuclei with the same mass number and atomic number that have different radioactive properties and can exist in any of several energy states for a measurable period of time.

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Other Word Forms

• isomeric adjective

Etymology

Origin of isomer

First recorded in 1865–70; back formation from isomeric

Compare meaning

How does isomer compare to similar and commonly confused words? Explore the most common comparisons:

• isotope vs. isomer
• isomer vs. enantiomer