An actor or actress is a person who portrays a character in a production. The actor performs "in the flesh" in the traditional medium of the theatre or in modern media such as film, radio, and television. The analogous Greek term is ὑποκριτής (hupokritḗs), literally "one who answers". The actor's interpretation of a role—the art of acting—pertains to the role played, whether based on a real person or fictional character. This can also be considered an "actor's role", which was called this due to scrolls being used in the theaters. Interpretation occurs even when the actor is "playing themselves", as in some forms of experimental performance art.

In fiction, a character is a person or other being in a narrative. The character may be entirely fictional or based on a real-life person, in which case the distinction of a "fictional" versus "real" character may be made. Derived from the Ancient Greek word χαρακτήρ, the English word dates from the Restoration, although it became widely used after its appearance in Tom Jones by Henry Fielding in 1749. From this, the sense of "a part played by an actor" developed. Character, particularly when enacted by an actor in the theater or cinema, involves "the illusion of being a human person". In literature, characters guide readers through their stories, helping them to understand plots and ponder themes. Since the end of the 18th century, the phrase "in character" has been used to describe an effective impersonation by an actor. Since the 19th century, the art of creating characters, as practiced by actors or writers, has been called characterization.