'Agency' is primarily a business representative device. It has been defined authoritatively by Gerald Fridman [Canadian Agency Law, 2d ed. (Markham: LexisNexis, 2012), at p.4] as:
Agency is the relationship that exists between two persons when one, called the agent, is considered in law to represent the other, called the principal, in such a way as to be able to affect the principal’s legal position by the making of contracts or the disposition of property.