Brussels is:

• the capital of Belgium, see Brussels
• a nickname of the institutions of the European Union, such as the European Commission whose headquarters is in Brussels, Belgium
• the name of two places in the United States:
  • Brussels, Illinois
  • Brussels, Wisconsin
• the name of a community in Ontario, Canada, see Brussels, Ontario

and can also refer to Brussels sprout.

Remarkably Belgium is also the name of two places in United States, in Illinois and Wisconsin as well.