An "agency" is a company that comes between a business and its customers. Customers go to the agency, which manages products and services from lots of different sources. Common examples are:

• real estate agencies
• ad (or "advertisement") agencies
• modeling agencies
• talent agencies (for actors, singers, etc.)

There's another meaning of "agency" as well, which is a government agency. A government agency is a group within the government that's responsible for one specific set of jobs. Well-known agencies in the United States include:

• The CIA (Central Intelligence Agency)
• The EPA (Environmental Protection Agency)