VALENCY
valence, valency
(noun) (chemistry) a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent)
valence, valency
(noun) (biology) a relative capacity to unite or react or interact as with antigens or a biological substrate
valency
(noun) the phenomenon of forming chemical bonds
Source: WordNet® 3.1
Etymology
Noun
valency (countable and uncountable, plural valencies) (mostly UK)
(graph theory) The number of edges connected to a vertex in a graph.
Synonym: degree
(especially, chemistry) Valence.
(linguistics) The capacity of a verb to take a specific number of arguments.
Synonym: valence
The capacity of something to combine with other things.
Source: Wiktionary
Val"en*cy, n.; pl. Valencies (. (Chem.)
(a) See Valence.
(b) A unit of combining power; a so-called bond of affinity.
Source: Webster’s Unabridged Dictionary 1913 Edition