The root or highest-level administrative unit in Microsoft Exchange Server, which is usually identified by the broadest name that can represent the enterprise’s business - the organization name cannot be changed without reinstalling all servers.
An Exchange organization consists of a number of sites, each of which consists of one or more Exchange servers. Sites are connected by connectors such as a Site Connector or Dynamic RAS Connector.
You can also use other connectors such as the Internet Mail Service Connector or X.400 Connector to provide messaging connectivity between your Exchange organization and a foreign mail system. Examples of such foreign mail systems include the following:
Graphic O-6. Organization in Microsoft Exchange Server.
In the Exchange directory hierarchy, which is displayed in the Exchange Administrator program, the Organization container contains