Frontier world was a term used to designate planets on the edge of a boundary.
Members of the Great Houses used "frontier world" to describe worlds on the frontier in time in the far future. These included Zo la Domini (PROSE: The Book of the War) and Frontios. (PROSE: Frontios)
Part of the Daleks' Great War took place along the frontier in space between Earth space and Draconian space. (PROSE: The Evil of the Daleks, TV: Frontier in Space) One historical account held that the Combined Galactic Resistance had seen action in this region during the conflict. (PROSE: The Whoniverse) During humanity's 41st century conflict against the New Dalek Paradigm, Ogrons from these so-called frontier worlds were captured and taken to Station 7. (COMIC: The Only Good Dalek)