A protectorate is a dependent nation-state that retains local government and internal security, but depends on a stronger nation-state for security. It is distinct from a government's member insofar as it has no voting rights within that government, and distinct from a colony in that a colony has no independent sovereignty and is directly governed, owned, and populated by a particular power.

In the case of Yogyakarta Baru -- established on a planet of Wolf 359, which is less than eight light-years from Earth and within Federation boundaries -- it is a protectorate, not a colony nor member world of the United Federation of Planets. It was founded before either the Coalition of Planets was founded in 2055 or the Federation was founded in 2161. The local government was reluctant to accept help, but its own military and exploration fleet was limited in terms of resources. (Star Trek: Shadowstar Station)

Terra 6 was a Federation protectorate whose population was made up of Humans from the mid- to late-20th century United States of America transplanted by the Preservers. It was called "Kentuckiana" by its inhabitants. In 2309, a Kzinti academic crashed his shuttle on Terra 6, necessitating that the USS Sagitarrius send a disguised landing party to rescue them. ("Wampus")