Novel. A substantial work of fiction, usually too long to be read at one sitting.
Novella. A work of fiction short enough to be read at one sitting, but only if the reader is willing to carry it to the bathroom several times.
Novelette. A work of fiction short enough to be read at one sitting, but too long to be read while waiting for the dentist.
Novellina. A work of fiction just long enough to occupy the time spent in the dentist’s waiting room.
Novellinetta. A work of fiction the proper length for reading on the phone screen while waiting in line at the grocery-store checkout.
Novellona. A very long work of fiction, to read which occupies a whole summer vacation.
Novellissima. A work of fiction stretched out over multiple volumes released over the course of several years and left unfinished at the author’s death.