** to represent the [[correlation coefficient]] of a population parameter
** to represent the [[شعاع طیفی]] of a matrix <math>A</math> denoted as <math>\rho(A)</math>
** to represent a [[Plastic number]]
* In [[علم اقتصاد]] to represent the discount rate of future pence cash flows
* In [[زیستشناسی مولکولی]] to represent the Rho protein responsible for termination of RNA synthesis. In such occasions, it is often represented as {{unicode|ϱ}} ("rho symbol" U+03F1), to avoid confusion with the Latin letter ''p''
* در [[برنامهنویسی]]
** For [[لاتک]], the symbols are <code>P</code> (Ρ), <code>\rho</code> (<math>\rho</math>), and <code>\varrho</code> (<math>\varrho</math>)
** The lower-case rho ''ρ'' has a special meaning in the [[ایپیال]]
