Meaning

noun an active and efficient cause; capable of producing a certain effect

noun a representative who acts on behalf of other persons or organizations

noun a substance that exerts some force or effect

originEtymology tree Proto-Indo-European *h₂eǵ- Proto-Indo-European *-eti Proto-Indo-European *h₂éǵeti Proto-Italic *agō Latin agō Latin agēnsder. English agent From Latin agēns, present active participle of agere (“to drive, lead, conduct, manage, perform, do”).

Etymology from Wiktionary, CC BY-SA 3.0