Agent

 

“One that acts for or in the place of another by authority from him: as a representative, emissary, or official of a government.”

 

Source: Webster’s Third New International Dictionary

 

“A person authorized by another (principal) to act for or in place of him; one entrusted with another’s business. One who represents and acts for another under the contract or relation of agency. One who acts for or in place of another by authority from him; a deputy, appointed by principal with power to do the things which principal may do.”

 

Source: Black’s Law Dictionary, 6^th Edition