The term 'Supreme Authority' can be defined by three different crossword solutions: MOTOWN (6 letters), TSAR (4 letters), and DOMINION (8 letters). MOTOWN is a record label founded in Detroit, Michigan in 1959. It was the most successful African-American owned record label of its time and is credited with launching the careers of many famous musicians. TSAR is a title used to refer to the ruler of Russia from 1547 to 1917. The TSAR was the absolute monarch of the country and held supreme authority over all of its citizens. DOMINION is a term used to refer to a self-governing nation or state that is part of a larger federation. In this context, it refers to the nations of Canada, Australia, and New Zealand, which are all part of the British Commonwealth and have their own governments but are still subject to the authority of the British Crown.