What is absolute refractive index? On what factors does it depend?

(N/A) Absolute refractive index: The refractive index of a medium with respect to vacuum (or in practice,air) is called its absolute refractive index.
$\therefore n = \frac{c}{v}$
Where $c$ is the speed of light in a vacuum and $v$ is the speed of light in the medium.
Dimensional formula of refractive index: $M^{0} L^{0} T^{0}$ (it is a dimensionless quantity).
The value of the refractive index of any medium depends on the following factors:
$1$. The nature of the medium.
$2$. The temperature of the medium.
$3$. The wavelength of the light used.