Role 

A role is a collection of privileges.

Like a privilege, a role can be assigned to a different role or to a user.

While privileges are always valid, roles are always inactive, i.e. the privileges they contain are not valid. Roles can be activated for individual sessions. Each user who is assigned a role can also define which roles are to be active in each of his or her sessions without having to define this in each individual session.

All roles are inactive for the current session while data definition commands are being executed.

See also:

Role name

CREATE ROLE statement