As defined by Merriam-Webster, noir is crime fiction featuring hard-boiled cynical characters and bleak sleazy settings.
Or, when in France (from Wiktionary):
Noir (adjective, masculine)
1. black in color
Ce chat est noir. (That cat is black.)
Il est noir.* (He is drunk.)
3. of black ethnicity
Il est noir.* (He is black.)
(*Not sure how to read the difference between examples two and three, but I'll leave that to the French to explain.)
Earlier this year I wrote my first noir piece (see American definition). Black Heart Magazine was kind enough to publish it. Robert Howell was kind enough to create a cover. My thanks to you both.
Here's the first sentence:
That's all you get here. For the rest, you'll have to go there.