Definition of valence in English:

valence

noun

another term for valency
‘The difference in the valence of phosphorous and silicon provides the free electrons needed for metal-like behaviour.’
another term for valency
‘These data can only be explained if one assumes that the affective valence of the prime is processed, even though this is not necessary for the task at hand.’

Origin

Late Middle English from late Latin valentia ‘power, competence’, from valere ‘be well or strong’.

Pronunciation

valence

/ˈveɪl(ə)ns/