Bouillabaisse is a traditional Provençal fish STEW originating from the port city of Marseille, France. It is made with a variety of different types of fish and shellfish, as well as vegetables, herbs, and spices. The term 'BOUILLABAISSE' is derived from the French words 'BOUILLON' (broth) and 'baisse' (to reduce). The STEW is often served with aioli, a garlic-flavored mayonnaise. The crossword solution for the term 'BOUILLABAISSE is one' is 'STEW', which accurately describes the dish as it is a type of STEW.