Definition of "Commonwealth" :

noun: a politically organized body of people under a single government

noun: a political system in which the supreme power lies in a body of citizens who can elect people to represent them

noun: a world organization of autonomous states that are united in allegiance to a central power but are not subordinate to it or to one another

noun: the official name of some states in the United States (Massachusetts and Pennsylvania and Virginia and Kentucky) and associated territories (Puerto Rico)