1 a an independent State or community, esp. a democratic republic. b such a community or organization of shared interests in a non-political field (the commonwealth of learning).
2 (the Commonwealth) a (in full the British Commonwealth of Nations) an international association consisting of the UK together with States that were previously part of the British Empire. b the republican period of government in Britain 1649-60. c US a part of the title of some of the States of the US. d the title of the federated Australian States.
Phrases and idioms:
Commonwealth Day a day each year commemorating the British Commonwealth (formerly called Empire Day).
Etymology: COMMON + WEALTH
Useful english dictionary. 2012.