The symbol referred to as rho (ρ) is a Greek letter commonly used to represent density in physics. It resembles a stylized "p" and can be included in Google Docs by copying and pasting it, although compatibility may depend on character encoding. Users can access a character map on Windows or OS X to find various versions of rho, including a curly variant. The discussion highlights the importance of distinguishing rho from the letter "p" in formulas, particularly in fluid dynamics. Overall, rho is a standard notation in physics, and various methods exist to incorporate it into documents.