valency

from WordNet (r) 3.0 (2006)

valency
    n 1: the phenomenon of forming chemical bonds
    2: (biology) a relative capacity to unite or react or interact
       as with antigens or a biological substrate [syn: {valence},
       {valency}]
    3: (chemistry) a property of atoms or radicals; their combining
       power given in terms of the number of hydrogen atoms (or the
       equivalent) [syn: {valence}, {valency}]

from The Collaborative International Dictionary of English v.0.48

Valency \Val"en*cy\, n.; pl. {Valencies}. (Chem.)
   (a) See {Valence}.
   (b) A unit of combining power; a so-called bond of affinity.
       [1913 Webster]

from The Free On-line Dictionary of Computing (8 July 2008)

degree
valency

   The degree (or valency) of a node in a graph is the number of
   edges joined to it.

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