Under the definition, the “enterprise” consists of “the related activities performed * * * for a common business purpose.” All of the activities comprising the enterprise must be “related.” Activities serving a single business purpose may be related, although different, but other activities which are not related are not included in the enterprise. The definition makes clear that the enterprise includes all such related activities which are performed through “unified operation” or “common control.” This is true even if they are performed by more than one person, or in more than one establishment, or by more than one corporate or other organizational unit. Specifically included, as a part of the enterprise, are departments of an establishment operated through leasing arrangements. On the other hand, the definition excludes from the “enterprise” activities only performed “for” the enterprise rather than as a part of it by an independent contractor even if they are related to the activities of the enterprise. Also, it makes clear that a truly independent retail or service establishment does not become a part of a larger enterprise merely because it enters into certain types of franchise or collective purchasing arrangements or because it has a common landlord with other such retail establishments.