the Act of Union
/ði ˌækt əv ˈjuːniən/
/ði ˌækt əv ˈjuːniən/
- (in the UK) either of two Acts of Parliament. The first Act of Union, in 1707, officially joined England and Scotland as one kingdom, called Great Britain, ruled by the parliament in London. The second Act of Union, in 1800, added Ireland to this group of countries, which was then called the United Kingdom of Great Britain and Ireland.