This is a matter of dispute among experts in literature, and is just a matter of definition. Folks that give out prizes have to be quantitative, though, so The Science Fiction and Fantasy Writers of America Nebula Award gives the following guidelines: Novel – 40,000 words or more; Novella – 17,500–39,999 words; Novelette – 7,500–17,499 words; Short Story – 7,499 words or fewer. Wikipedia says ("Length of a novel" article) Novel over 50,000 Novella 20,000 to 50,000 Novelette 7,500 to 20,000 Short story 1,000 to 7,500

novel is 1.An extended fictional work in prose; usually in the form of a story 2.A printed and bound book that is an extended work of fiction "his bookcases were filled with nothing but novels"; "he burned all the novels" short story is 1.A prose narrative shorter than a novel cowboy...

novel: معناها راوية وهي بتكون كبيرة ال حد ما وغالبا بتكون خيالية , story: معناها قصة اما لتسلية وهذا الاجح واما احداث معينة واما اخبار ويكون منها الواقعي ومنها الخيالي