noun Physics, Chemistry.
the quantitative measure, usually given in electron-volts, of the tendency of an atom or molecule to capture an electron and to form a negative ion.
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British Dictionary definitions for electron affinity
a measure of the ability of an atom or molecule to form a negative ion, expressed as the energy released when an electron is attachedSymbol: A
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