What is a set meal?

In a restaurant, a set menu is a term used to mean a fixed menu. This means that the customer or diner either has no choice, or very limited choice of menu. For example, at a banquet where a fixed menu is served, every guest might receive the same meal of salad, roast chicken, potatoes and vegetable, and bread with chocolate mousse for dessert. Individual guests usually do not have the option of getting strawberry ice cream instead of the chocolate mousse, for example. (Although, in cases where the customer is allergic to a food or a vegetarian, some substitutions may be made.)
In a restaurant, a fixed menu means that the customer purchases a dinner with a menu that's pre-determined by the restaurant, usually at a slightly lower price. For example, if you are ordering off the regular menu, you might have a choice between lobster, steak or grilled fish, at prices from $15 to $40. Usually, appetizers and desserts are additional, when ordering off the menu. The fixed menu might be soup, turkey with dressing, vegetables and pumpkin pie, with a glass of wine, all for $19.95.