Definition of "Agency" :

noun: thing or person that acts to produce a particular effect or achieve an end

"An example is the best agency of instruction."

noun: a business or organization that provides a particular service, especially the mediation of transactions between two parties

noun: an administrative unit of government

"The Central Intelligence Agency."

noun: the state of serving as an official and authorized delegate or agent

noun: the state of being in action or exerting power

"The agency of providence."