Merriam-Webster Collegiate Dictionary - valence

 noun  Etymology: Late Latin valentia power, capacity, from Latin valent-, valens, present participle of valere to be strong — more at wield  Date: 1884  1. the degree of combining power of an element as shown by the number of atomic weights of a monovalent element (as hydrogen) with which the atomic weight of the element will combine or for which it can be substituted or with which it can be compared  2.  a. relative capacity to unite, react, or interact (as with antigens or a biological substrate)  b. the degree of attractiveness an individual, activity, or thing possesses as a behavioral goal the relative potency of the ~s of success and failure — Leon Festinger VALENCE  geographical name commune SE France S of Lyon population 65,026