A meal is an instance of eating, specifically one that takes place at a specific time and includes specific, prepared food.
Meals occur primarily at homes, restaurants, and cafeterias, but may occur anywhere. Regular meals occur on a daily basis, typically several times a day. Special meals are usually held in conjunction with such occasions as birthdays, weddings, anniversaries, and holidays.
A meal is different from a snack in that meals are larger, more varied, and more filling, while snacks are more likely to be small, high-calorie affairs; however, any food eaten in small amounts at an unscheduled time can be classified as a snack.
A picnic is an outdoor meal where one brings one's food, such as a sandwich or a prepared meal (sometimes in a picnic basket). It often takes place in a natural or recreative area, such as a park, forest, beach, or grassy lawn. On long drives a picnic may take place at a road-side stop such as a rest area.
A banquet is a large, often formal, and elaborate meal with many guests and dishes.