the quality that determines the number of atoms or groups with which any single atom or group will unite chemically.
the relative combining capacity of an atom or group compared with that of the standard hydrogen atom. The chloride ion, Cl–, with a valence of one, has the capacity to unite with one atom of hydrogen or its equivalent, as in HCl or NaCl.
Immunology. the number of determinants per molecule of antigen.
the capacity of one person or thing to react with or affect another in some special way, as by attraction or the facilitation of a function or activity.
Also, valency.

1865–70; < Latin valentia strength, worth, equivalent to valent- (stem of valēns), present participle to be strong + -ia noun suffix; see -ence

valance, valence. Unabridged


a city in and the capital of Drôme, in SE France.


a department in SE France. 2533 sq. mi. (6560 sq. km). Capital: Valence. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
Drôme (French drom)
a department of SE France, in Rhône-Alpes region. Capital: Valence. Pop: 452 652 (2003 est. Area: 6561 sq km (2559 sq miles)

valence (ˈveɪləns)
1.  another name (esp US and Canadian) for valency
2.  the phenomenon of forming chemical bonds

Valence (French valɑ̃s)
a town in SE France, on the River Rhône. Pop: 64 260 (1999)

valency or esp (US and Canadian) valence (ˈveɪlənsɪ)
n , pl -cies, -ces
1.  chem a property of atoms or groups, equal to the number of atoms of hydrogen that the atom or group could combine with or displace in forming compounds
2.  linguistics the number of satellite noun phrases with which a verb combines: the English verb `give' takes a subject and two objects, so it has a valency of three
3.  immunol
 a.  the number of antigen-binding sites on an antibody molecule
 b.  the number of antigen-binding sites with which an antigen can combine
[C19: from Latin valentia strength, from valēre to be strong]
valence or esp (US and Canadian) valence
[C19: from Latin valentia strength, from valēre to be strong]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Word Origin & History

early 15c., "extract, preparation," from L. valentia "strength, capacity," from valentem (nom. valens), prp. of valere "be strong" (see valiant). Meaning "combining power of an element" is recorded from 1884, from Ger. Valenz (1868), from the L. word.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

valence va·lence (vā'ləns) or va·len·cy (-lən-sē)

  1. The combining capacity of an atom or a radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.

  2. A positive or negative integer used to represent this capacity.

  3. The number of components of an antigen molecule to which an antibody molecule can bind.

  4. The attraction or aversion that an individual feels toward a specific object or event.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
valence   (vā'ləns)  Pronunciation Key 
A whole number that represents the ability of an atom or a group of atoms to combine with other atoms or groups of atoms. The valence is determined by the number of electrons that an atom can lose, add, or share. An atom's valence is positive if its own electrons are used in forming the bond, or negative if another atom's electrons are used. For example, a carbon atom can share four of its electrons with other atoms and therefore has a valence of +4. A sodium atom can receive an electron from another atom and therefore has a valence of -1. (In this book the distinction between positive and negative valences is ignored unless it is relevant.) The valence of an atom generally indicates how many chemical bonds it is capable of forming with other atoms. Also called valence number, oxidation state.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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American Heritage
Cultural Dictionary
valence [(vay-luhns)]

A number characterizing an atom, equal to the number of valence electrons.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Encyclopedia Britannica


town, capital of Drome departement, Rhone-Alpes region, southeastern France. Valence lies on the left bank of the Rhone River. Built on a succession of terraces bordering the Rhone, the town is dominated by the ancient Cathedral of Saint-Apollinaire, which was consecrated by Pope Urban II in 1095 and completed early in the 12th century. Damage done to the cathedral during the Wars of Religion (1569-98) was repaired in the 17th century. The Champ de Mars, a vast esplanade south of the cathedral, offers a fine view of the Rhone River valley. Valence probably became a bishopric in the 4th century and was ruled by its bishops until Louis XI in 1450 persuaded them to give up their temporal power in exchange for royal protection and a university (suppressed after the French Revolution).

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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