With the word "audience" I mean to include the possibility that there is only one person in the audience, who might even be the person who created the art work (for example, reading one's own manuscript; reciting one's own poem; or viewing and/or touching one's own sculpture). Of course, the audience could also involve many and could exclude the person who created the work.
Note
1This definition, while strictly mine, with the help of the following sources evolved such that it satisfied me far more:
• the definition of art that Ayn Rand presented in her book, The Romantic Manifesto
• the reconstruction of Ayn Rand's esthetic and literary philosophy that Chris Matthew Sciabarra provided in his book, Ayn Rand: The Russian Radical
• various of Marshall Rosenberg's discussions of the nature of - including the stimuli and causes for - emotional responses, especially in his book, Nonviolent Communication: A Language of Life.