What is the meaning of agency?

noun

• An administrative unit of government.
  • usage: "the Central Intelligence Agency"; "the Census Bureau"; "Office of Management and Budget"; "Tennessee Valley Authority"
  • synonyms: federal agency, government agency, bureau, office, authority
• A business that serves other businesses.
• The state of being in action or exerting power.
  • usage: "the agency of providence"; "she has free agency"
• The state of serving as an official and authorized delegate or agent.
  • synonyms: representation, delegacy
• How a result is obtained or an end is achieved.
  • usage: "a means of control"; "an example is the best agency of instruction"; "the true way to success"
  • synonyms: means, way