chemistry vs valency

chemistry and valency both are nouns.

Word	Noun	Adjective	Verb	Adverb
chemistry	Yes	No	No	No
valency	Yes	No	No	No

chemistry (noun)	valency (noun)
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions	(chemistry) a property of atoms or radicals; their combining power given in terms of the number of hydrogen atoms (or the equivalent)
the way two individuals relate to each other	(biology) a relative capacity to unite or react or interact as with antigens or a biological substrate
the chemical composition and properties of a substance or object	the phenomenon of forming chemical bonds