The density symbols in physics are represented by the Greek letter 'ρ' (rho), which is a four-letter word. Density is a physical property of matter that is defined as the mass per unit volume of a substance. It is an important concept in physics, as it is used to calculate the pressure, temperature, and other properties of a material. The symbol for density is typically written as 'ρ' or 'ρ/V', where 'V' is the volume of the material.