From Lexicanum

Cardinal worlds are one of the subtypes of the Civilised World classification, and share the same properties such as self-sufficiency and at minimum, a moderate technological level. They are Ecclesiarchy worlds, ruled directly by the Ministorum, with the planetary governor also being Cardinal. Temples and other religious sanctuaries often cover vast areas of the planet.

Sources

• ¹:Warhammer 40,000 3rd Edition Rulebook p. 114

Worlds of the Galaxy

Imperium	Adeptus Astartes Homeworld • Agri World • Cardinal World • Civilised World • Dead World • Death World • Desert World • Feral World • Feudal World • Forge World • Hive World • Ice World • Industrial World • Jungle World • Knight World • Mining World • Ocean World • Paradise World • Penal World • Research Station • Shrine World
Xeno	Xenos World • Daemon World • Exodite World • Tomb World • Maiden World • Crone World • Ork World • Tau Empire • Craftworld