The term 'Density Symbol' refers to a variety of symbols used to represent the density of a material or substance. The most common symbols are RHO (3 letters), RHOS (4 letters), DODO (4 letters) and TESLA (5 letters). RHO is the Greek letter that is used to represent density in physics, while RHOS is the symbol for the density of a solid. DODO is the symbol for the density of a liquid, and TESLA is the symbol for the density of an electric field.