Role

Why
The role is important because it allows us to specify an action that only somebody with a particular role can perform

What
A role is a set of a users that are allowed to perform a certain task. This can be, for example, acting captain of the watch. There may be lots of groups such as sailors, captains, admiral, etc. However, any one of these people from these groups can assume the role of captain of the watch based on a chain of command