That branch of science which treats of the composition of substances, and of the changes which they undergo in consequence of alterations in the constitution of the molecules, which depend upon variations of the number, kind, or mode of arrangement, of the constituent atoms. These atoms are not assumed to be indivisible, but merely the finest grade of subdivision hitherto attained. Chemistry deals with the changes in the composition and constitution of molecules. See Atom, Molecule.
- The science of the composition, structure, properties, and reactions of matter, especially of atomic and molecular systems.
- The composition, structure, properties, and reactions of a substance.
- The elements of a complex entity and their dynamic interrelation: "Now that they had a leader, a restless chemistry possessed the group” ( John Updike).
- Mutual attraction or sympathy; rapport: The chemistry was good between the partners.