Realm is the dominions of a king (or queen); a kingdom.
Realm may also more broadly refer to everything which falls within a certain set of parameters and may specifically refer to:
Maths and scienceEdit
- Realm (database), an object database and platform created primarily for mobile devices maintained by Realm Inc.
- A URL pattern in OpenID protocol, for which the OpenID authentication is valid
- An ID for an instance of a server software- HTTP transmits Realm when answering to a Basic access authentication request to distinguish different areas on server
- A scope of operation in networking or in security — as in Active Directory realms
- Realm, an American progressive thrash metal band
- Realm (magazine), a British coffee-table magazine
- Realm Media, formerly Serial Box, an American audio entertainment company
- "Realms", a song by Hawkwind from Space Bandits
- The Realm (film), a 2018 Spanish thriller film