Sentence:  Despite the sheer beauty and spectacle of numerous documentaries , art films , and travelogues , despite the impressive financial success of such a recent development as Cinerama , the movies are at heart a <WSD>form</WSD> of fiction , like the play , the novel , or the short story . 
Meaning of the word marked with <WSD> tags:  a category of things distinguished by some common characteristic or quality