Meaning

noun the phenomenon of forming chemical bonds

noun (biology) a relative capacity to unite or react or interact as with antigens or a biological substrate

noun (chemistry) a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent)

originFrom Late Latin valentia and Latin valentia (“bodily strength; health; vigour”) + English -y (suffix forming abstract nouns denoting a condition, quality, or state). Valentia is derived from valēns (“healthy, strong, vigorous”) + -ia (suffix forming feminine abstract nouns); while valēns is the present active participle of valeō (“to be healthy, sound, or well; to be strong; to have influence or…

Etymology from Wiktionary, CC BY-SA 3.0