What exactly does ${\rm PGL}(n,K)$ represent?

Question

Suppose $V:=GL(n,K)$ denotes the general linear group and $V_I$ denotes center of $V$. Then what exactly does $V/V_I$ represent? I would be appreciate if you give a similar good example for better understanding. (The origin of this question is General projective transformations ${\rm PGL}(n,K)$ and special projective transformations ${\rm PSL}(n,K)$)