It's a spicy sauce served with pasta, generally made with black olives, garlic, tomatoes, onions, and anchovies all cooked in olive oil.
The name puttanesca is actually a derivation of the Italian word puttana, which means (are you ready for this?) "whore." Yep everyone, when you order your favorite spicy dish of Spaghetti all Puttanesca, you're actually ordering "Whore's spaghetti." The reason why it's called that is highly debated, however one version says it's a reference to the sauce's hot, spicy flavor and smell, another says it's from the fact that it was a quick cheap meal prostitutes could prepare between customers. Either way, it's a pretty interesting name. Who knew?!