I do not know what "division of physics" specifically refers to. If you are looking for the axiomatization of physics (one of Hilbert's problems), read the article below: http://en.wikipedia.org/wiki/Hilbert%27s_sixth_problem
Physics is the field of science that studies the physical world. From the large (galaxies, planets, etc) to the small (how proteins fold, atoms, etc) physics plays a role. It is a natural science...
It means that how many units present in each unit of demoniacal value. For example, density is equal to mass divided by volume, which means that how many kilogram is the matter in 1 cm^3.