Silly me, thinking that it should mean it’s written sometime within my lifetime, or to be more flexible, within the lifetimes of some of those old folks still living today.
I was browsing Amazon and I see that among the authors they list for contemporary fiction are Charles Dickens, Alexandre Dumas, and Herman Melville among others. I haven’t looked hard enough to find who is the oldest contemporary fiction writer, but clearly they’re going back a couple of centuries.
To be fair to Amazon, Googling the term came up with a few definitions that would agree with them, primarily the idea that the time described in a fictional work is contemporary with the author’s life irrespective of the reader. But by that definition, Silas Marner could be contemporary fiction, and IMO that one hellaciously too boring a book over the line.
Still, Mark Twain and his language stand up pretty well against more modern styles, as does Conan Doyle, so… IMO Dickens doesn’t pass this test. Reading his books (to me) is more an exercise in the study of literary history than it is about sheer enjoyment of the work. So maybe the definition should be more about contemporary language than about contemporary times.
Wiki doesn’t have a definition for it, but it does for contemporary literature, which one of the Wiki Gods has declared to be – set in post WWII times. That kinda works for me as a reasonable divider, and I realize that the goalposts of contemporary fiction will (and should) be moving as generations pass.
How should it be defined? Need answer fast! 
What are you talking about? In contemporary literature, these books are listed:
In classics, these books are listed:
So classics go up to at least the 1960’s. There are very few books in the contemporary literature section that aren’t by living authors. There are a few books in both sections.
Contemporary means that it is set in the time it was written in, which technically applies to Dickens and Melville. (Not sure about Dumas).
But advertisers generally don’t use it that way. When they say contemporary they usually mean “now”, because that’s what the public expects.
1851 is history to us, but to Melville it would have been “now”.
So accurate but misleading.
Wendell, if you do a search in that Contemporary Literature link you’ll find thousands of hits for Dickens, Dumas, and Melville, as many as you find if you search under Classics. I don’t understand why, but my guess is that some people don’t want to buy classic literature because of the school room connotations so Amazon fudges it.
Personally, I would draw the line at WWI, for two reasons.
First, literature really did change around that time because it was affected by the Modernist movement that hit almost all the arts. Sherwood Anderson, Ernest Hemingway, James Joyce, T. S. Eliot all get started in the 1914-1918 era and/or wrote their most influential work shortly after. It didn’t appear out of nowhere, of course - Gertrude Stein started pre-war and Huck Finn reads like it was written a century after Jules Verne - but the movement is the biggest dividing line in literature.
Second, there are many people still alive and reading who found these authors when they were alive and publishing. If you are old enough to remember looking forward to the next book by Hemingway or Faulkner, then these authors are contemporary with your life and experiences even if some of their works were published before you were old enough to read them when they first appeared. That can’t be said for Twain, who died in 1910, no matter how advanced he was. My high school assigned literally no books written after 1950 in my English courses, and the only post WWI books were essentially high level children’s literature like Johnny Tremain. Modernist books were apparently too contemporary for them. English was about the classics.
Boyo Jim is obvious correct that the line moves with the years. My definition is just slightly more expansive than his. In another generation maybe the modernists will seem too old to be included and the post WWII writers will be as far back as anyone is willing to accept. But maybe not. The 20s are remarkably modern in many ways. As I’ve said before, the 30s, 40s, and 50s are the weird decades; if you cut them out the 20s and 60s make perfect sense next to one another. It’s like Africa and South America fitting together - the Atlantic Ocean is the oddity. The 60s New Wave that swept through all the arts was a late blooming of modernism. You can’t write well about 60s literature without referencing 20s literature. So the 20s may stay a lot longer than the time span indicates.
It’s not particularly relevant to my choice to read something, or my estimation of it, but if I had to draw a line it would be well within my lifetime. “Contemporary” in this application to me would most usefully mean something that tied into a present zeitgeist. Something that was unanachronistically set in the 1970s would not be “contemporary” to me now.
I just went through the first few pages of the classic and contemporary literature picks on Amazon. I didn’t look any further than that. Now that I do, it’s an even stupider distinction than I thought. I don’t know and don’t care whether there is any useful distinction between classic and contemporary literaure, but it’s clear that the distinction that Amazon makes (or fails to make) is incomprehensible.