1. An organization, especially a company, that acts as the agent, representative, or subcontractor of a person or another company.
2. An administrative division of a government or international organization; such as, a United Nations agency.
3. The building or offices where an agency is located.
4. The action, medium, or means by which something is accomplished.
5. A legal relationship involving a person, the principal, and someone else who acts for the person, the agent; or the area of the law concerned with such relationships.