Role

A role is a group of privileges that can be granted to database users, user groups, or to other roles.

While privileges apply at all times, roles are initially inactive, which means that the privileges they contain do not apply. You can activate roles for individual database sessions. Every database user to whom roles have been assigned can also define which roles should be active in each database session. The database user can change this definition after opening a database session.

SQL Reference Manual, Role Name (role_name)

SQL Tutorial, Roles