Executive Chef, also known by the term Chef de Cuisine, is the professional pinnacle to which many chefs aspire. Chef’s are kitchen managers so payroll, food-cost, personnel management, menu creation and essentially everything that happens in the kitchen falls within their scope of responsibility.
Sous Chef, or Assistant Chef, is the right-hand to the Executive Chef. Sous Chefs manage a staff of assistant chefs, cooks and kitchen workers, as well as creating dishes for the menu.
Senior Chef, formally called Chef de Partie, is assigned one particular menu specialty in which he or she excels. Senior Chef directs the prep work of kitchen staff and assistant cooks in his or her area.
Demi Chef is very similar to Senior Chef. Customarily this chef would specialize in one type of dish and perhaps direct the prep work of staff key to that specialty. A good example would be sushi chefs.
Pastry Chef are responsible for creating chocolates, breads, and pastries that find their way to the dessert menu. They work in concert with bakers, chocolatiers and others dessert and pastry specialists.