According to Larousse Gastronomique, the name of the classic French fish soup bouillabaisse is derived from two words: bouillir (to boil) and abaisser (to reduce). It refers more to a cooking method than a recipe, since, as with so many dishes, there is no definitive formula, with cooks adding whatever they have on hand. The dish originated in Marseille, a large port on the Mediterranean coast. At Bistro Moderne (2525 West Loop South, 713-297-4383), the bouillabaisse ($22.99) contains a rich, thin tomato broth mixed with wine and olive oil and heavily laced with basil, fennel and other spices. It also has potatoes, along with mussels, clams, scallops, shrimp, whitefish and salmon. There’s enough to fill a large soup bowl, which would traditionally have two slices of crispy bread on the bottom. But here the bread is served on the side with a lemon-aioli, which is, in itself, worth the price of admission.