Chemistry. a compound displaying isomerism with one or more other compounds.
Also called nuclear isomer. Physics. a nuclide that exhibits isomerism with one or more other nuclides.
Origin of isomer
First recorded in 1865–70;
back formation from isomeric
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for isomers
Historical Examples of isomers
One class of isomers was unexplained, and an explanation was demanded.
Isomers: that series of Coleoptera in which the tarsi have an equal number of joints on all feet.
Here we have assumed the substituent groups to be alike; when they are unlike, a greater number of isomers is possible.
In the case of tetra-substituted compounds, thirty isomers are possible when all the groups are different.
The next members are the isomers anthracene and phenanthrene, C14H10, formed from three benzene nuclei.
British Dictionary definitions for isomers
Derived Formsisomeric (ˌaɪsəˈmɛrɪk), adjective
chem a compound that exhibits isomerism with one or more other compounds
physics a nuclide that exhibits isomerism with one or more other nuclides
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for isomers
1866, back-formation from isomeric; cf. Greek isomeres "sharing equality," from iso- (see iso-) + meros "part, share" (see merit (n.)).
Online Etymology Dictionary, © 2010 Douglas Harper
Related formsi′so•mer′ic (-mĕr′ĭk) adj.
Any of two or more substances that are composed of the same elements in the same proportions but differ in properties because of differences in the arrangement of atoms.
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.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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.
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.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
In chemistry, molecules that contain exactly the same numbers of the same kinds of atoms, but in which the atoms have different structural arrangements.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.