DDS Foundation Wiki

A communication context, which provides a virtual environment, encapsulating different concerns and thereby optimizing communications. DDS applications send and receive data within a domain, which provides a virtual communication environment for participants having the same domain id. This environment also isolates participants associated with different domains, i.e., only participants within the same domain can communicate, which is useful for isolating and optimizing communication within a community that shares common interests.

Source: OpenSplice Glossary