chemistry

(noun) the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions. Synonyms: chemical science.

(noun) the chemical composition and properties of a substance or object. Example: "The chemistry of soil."

(noun) the way two individuals relate to each other. Synonyms: interpersonal chemistry, alchemy. Examples: "Their chemistry was wrong from the beginning -- they hated each other." "A mysterious alchemy brought them together."