SQL> show user
USER is "SCOTT"
SQL> select * from dictionary where table_name like '%ROLE%';

TABLE_NAME           COMMENTS
-------------------- --------------------------------------------------
USER_ROLE_PRIVS      Roles granted to current user
ROLE_ROLE_PRIVS      Roles which are granted to roles
ROLE_SYS_PRIVS       System privileges granted to roles
ROLE_TAB_PRIVS       Table privileges granted to roles
SESSION_ROLES        Roles which the user currently has enabled.

SQL>