Realm
This page may be moved to Wiktionary.Realm is an old term still used as an alternative word for kingdom. It is particularly used for those states which use the word Kingdom in the title (for example, the United Kingdom), to avoid clumsy repetition of the word kingdom in a sentence. For example The Queen's realm, the United Kingdom . . .
It is also frequently used to refer to territories "under" a monarch, yet not a physical part of his or her "kingdom"; for example, the various Commonwealth Realms under the British crown. The Cook Islands, Niue, and Tokelau are considered parts of the "Realm of New Zealand", though they are not part of New Zealand proper. Likewise, the Faroe Islands and Greenland are part of the "Danish Realm".
In Java-J2EE realm terms a database containing users, usergroups and their roles (sets of permissions to access server-resources). Optionally a realm manages user-passwords, certificates and authentication logic.