The Oxford Thesaurus An A-Z Dictionary of Synonyms - realm n.

1) domain, kingdom, empire, monarchy, principality, palatinate, duchy or dukedom: They searched the realm for a girl whose foot would fit into the glass slipper. 2) territory, area, bailiwick, department, responsibility, jurisdiction: Collecting taxes is not within the realm of our office. 3) area, confines, sphere, limits: Cooperation with foreign companies is certainly well within the realms of possibility.