NeoArthian is a term used to refer to the cultures, peoples and other aspects of civilisations which directly descended from the Arthian Empire. Today, the majority of NeoArthian races and civilisations are part of Delta and no other NeoArthian Interstellar Powers remain.

NeoArthian also refers to a constructed language, based on Ancient Arthian, used for communication between the many NeoArthian Races, most of which use a language based on arthian. It is the official language of Delta.