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 isomer
Historical Examples of isomer
Sometimes either form was digestible, but frequently the body could use only the isomer to which it was adjusted.
According to this view hyoscyamine ought to be the hyoscinate of hyoscine, or at any rate an isomer of this body.
An isomer of chloral, parachloralide, is made by passing excess of dry chlorine into absolute methyl alcohol.
Besides this oil, cloves also contain two neutral bodies, eugenin and caryophyllin, the latter of which is an isomer of camphor.
Chavibetol, an isomer of eugenol, occurs in the ethereal oil obtained from Piper betle.
British Dictionary definitions for isomer
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 isomer
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.