a city in the Netherlands. In 1991, the leaders of the countries in the EU (=European Union) met there and made an agreement to become more politically and economically united. This agreement, called the Maastricht Treaty, was signed in 1992. The main aim of the Treaty is to establish the principle of closer economic union in the EU and a singlecurrency (=system of money), and it also includes the Social Chapter, which deals mainly with the rights of workers.
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.