The refractive index of a diamond is 2.42. What is the meaning of this statement?

Refractive index

1. It is defined as the ratio of the speed of light in a vacuum to its speed in a specific medium. It is denoted by n with $n=\frac{c}{v}$.
2. The above statement means that the speed of light in a diamond is $\frac{1}{2.42}$ times the speed of light in a vacuum.
3. As the refractive index of a diamond is quite high, the speed of light in a diamond will reduce by a factor of 2.42 as compared to its speed in air.