Molecule, n.: The ultimate, indivisible unit of matter. It is distinguished from the corpuscle, also the ultimate, indivisible unit of matter, by a closer resemblance to the atom, also the ultimate, indivisible unit of matter ... The ion differs from the molecule, the corpuscle and the atom in that it is an ion.
Ambrose BierceGRAVITATION, n. The tendency of all bodies to approach one another with a strength proportioned to the quantity of matter they contain-the quantity of matter they contain being ascertained by the strength of their tendency to approach one another. This is a lovely and edifying illustration of how science, having made A the proof of B, makes B the proof of A.
Ambrose Bierce