Physics (?), n. [See Physic.] The science of nature, or of natural objects; that branch of science which treats of the laws and properties of matter, and the forces acting upon it; especially, that department of natural science which treats of the causes (as gravitation, heat, light, magnetism, electricity, etc.) that modify the general properties of bodies; natural philosophy.
[1913 Webster]

&hand_; Chemistry, though a branch of general physics, is commonly treated as a science by itself, and the application of physical principles which it involves constitute a branch called chemical physics, which treats more especially of those physical properties of matter which are used by chemists in defining and distinguishing substances.
[1913 Webster]