Charter of Fundamental Rights
The charter recognises a number of rights - such as freedom of speech and fair working conditions - but will not be incorporated into European law.
Closer co-operation
Also known as reinforced or enhanced co-operation, it allows some countries to forge ahead on certain issues, giving rise to fears of a 'two-speed' Europe.
Council of Ministers
The council directly represents the EU's member governments in a "cabinet of cabinets".
Enlargement
Twelve countries are negotiating their membership of the EU - but all must pass strict tests before being allowed in.
Euro
After 20 years in the making, the single European currency now exists, but it has had a tough start.
European Central Bank
The European Central Bank is responsible for the launch of the euro and European monetary policy.
European Commission
The executive body of the EU consists of 20 commissioners and is the driving force behind new legislation.
European Court of Auditors
The court is the "financial conscience" of the European Union, tracking the management of EU money.
European Court of Justice
The judicial institution of the EU, founded in 1952, its job is to monitor the even interpretation of European law across the union.
European Parliament
The parliament is the only directly elected body in the European Union and the only elected international assembly in the world.