Density can be used in a sentence showing its scientific meaning by defining the term. In definition, you are giving the scientific meaning of the word density and at the same time you are constructing a sentence. For example :
Density is the mass per volume of the material. Basically, it refers to the measurement of how crammed together is the matter. The formula to calculate density is rho = m/v wherein rho is the density, m stands for the mass and v stands for the volume.