In preparation for a fiction course for the MFA Creative Writing Program at Otis College of Art this Fall, I reread Ronald Firbank's fiction Valmouth, and sought out his biography on Wikipedia, where I read the author "produced a series of novels."
Since I consider myself a sort of authority of the various genres of fiction, I am no longer surprised to see that any fiction is described by most readers these days as a "novel." And, although the genre, "novel," seems to me to center on a central figure, charting his or her relationship (often in symbolic terms) with the larger culture or, at least, the world outside the central figure, I have become somewhat indifferent if people use the term "novel" indeterminately.
The only times it truly upsets me is when readers have difficulty with a work of fiction because it does not meet the standard expectations of a "novel," such as the case of Djuna Barnes' anatomy Nightwood, a work that wasted the energies of at least one critic, Joseph Frank, in creating a new form (what he called "spatial fiction") to explain what he saw as anomalies, all perfectly a home in the anatomy genre. Others have approached the epic fictions of Heimito von Doderer and Robert Musil, works whose structures often work more like musical compositions than plot-organized novels, similarly.