domain

Any tree or subtree within the Domain Name System (DNS) namespace. Domain most commonly refers to a group of computers whose host names share a common suffix, the domain name.

In Oracle Names, a domain is a logical group of computers and network services. A domain is a way to identify a service within a network. Similar to a directory structure in a file system, it assigns a unique logical name to a network service. Within each domain all names must be unique, but across domains simple unqualified names can be repeated.