What is an instance of an artwork?

The expression ‘an instance of an artwork’ is often used in philosophical discourse about art. Yet there is no clear account of what exactly this expression means. My goal in this essay is to provide such an account. I begin by expounding and defending a particular definition of the concept of ‘an instance of an artwork’. Next, I elaborate this definition – by providing definitions of the main derivatives of the concept of ‘an instance of an artwork’, namely the concepts of ‘a well-formed instance of an artwork’ and ‘a non-wellformed instance of an artwork’. Finally, I examine the relation of the foregoing definitions to the existence and identity conditions of artworks and make some additional remarks concerning these definitions.