A superstate is defined as "a large and powerful State formed when several smaller countries unite", "A large and powerful state formed from a federation or union of nations". This is distinct from the concept of superpower, although these are frequently seen together. It is also distinct from the concept of empire, where one nation dominates other nations through military, political, and economic power, although an empire may also be a superstate.
In the early 20th century, "superstate" had a similar definition as today's supranational organisations. In a 1927 article by Edward A. Harriman on the League of Nations, a superstate was defined as merely "an organisation, of which a state is a member, which is superior to the member themselves", in that "[a] complete superstate has legislative, executive and judicial organs to make, to execute and to interpret its laws". According to this definition, Harriman saw the League of Nations as a "rudimentary superstate", and the United States as "an example of a complete and perfect superstate".
In World Order of Bahá'u'lláh, first published in 1938, Shoghi Effendi, the Guardian of the Bahá'í Faith, described the anticipated world government of that religion as the "world’s future super-state" with the Bahá'í Faith as the "State Religion of an independent and Sovereign Power."
In contemporary political debate, especially the one centred on the European Union, the term "superstate" is used to indicate a development in which the Union takes over the character of a State. For instance, Glyn Morgan opposes the perspective of a "European superstate" to the ones of "a Europe of nation-states" and of "a post-sovereign European polity".:202 In her definition, a "European superstate is nothing more than a sovereign state - a tried and tested type of polity that predominates in the modern world - operating on a European wide scale",:204 i.e., "a unitary European state".:ix Especially after the European debt crisis, economic literature started to discuss the role of European union as a European superstate. In particular,  compared the emergence of a debt union to the federal structure of Germany.
The term was famously used by Margaret Thatcher in her 1988 Bruges speech, when she decried the perspective of "a European super-state exercising a new dominance from Brussels", and has since entered the eurosceptic lexicon. Tony Blair argued in 2000 that he welcomed an EU as a "superpower, not a superstate".
- "Superstate", Cambridge dictionaries online
- Oxford dictionaries
- Edward A. Harriman, The League of Nations a Rudimentary Superstate, American Political Science Review / Volume 21 / Issue 01 / February 1927, pp 137-140
- Effendi, Shoghi (1938). "Local and National Houses of Justice". The World Order of Bahá’u’lláh. Wilmette, Illinois, USA: Bahá'í Publishing Trust. p. 7. ISBN 0-87743-231-7.
- V. K. WICKRAMASINGHE, JAPAN — THE EMERGING SUPERSTATE ? Some Thoughts on Herman Kahn. The Developing Economies, Volume 11, Issue 2, pages 196–210, June 1973
- Glyn Morgan, The Idea of a European Superstate: Public Justification and European Integration
- Erkut 
- Margaret Thatcher, Speech to the College of Europe ("The Bruges Speech"), 20 September 1988
- Stephen Haseler, Super-State: The New Europe and Its Challenge to America, p. 85