Acting is an activity in which a story is told by means of its enactment by an actor or actress who adopts a character—in theatre, television, film, radio, or any other medium that makes use of the mimetic mode.
Performance is completion of a task with application of knowledge, skills and abilities. In work place, performance or job performance means good ranking with the hypothesized conception of requirements of a task role, whereas citizenship performance means a set of individual activity/contribution (prosocial organizational behavior) that supports the organizational culture. In the performing arts, a performance generally comprises an event in which a performer or group of performers present one or more works of art to an audience. Usually the performers participate in rehearsals beforehand. An effective performance is determined by competency of the performer - level of skill and knowledge. Spencer and McClelland in 1994 defined competency as "a combination of motives, traits, self-concepts, attitudes, cognitive behavior skills (content knowledge)" that helps a performer to differentiate themselves superior from average performers. A performance may also describe the way in which an actor performs. In a solo capacity, it may also refer to a mime artist, comedian, conjurer, or other entertainer.
On the stage he was natural, simple, affecting,'Twas only that when he was off, he was acting.
Oliver Goldsmith, Retaliation (1774), line 101.