A course is a specific set of food items served together during a meal, all at the same time.
For instance, a hamburger served with French fries would be considered a single course and might constitute the entire meal.
Courses may vary in size as well as number depending on the culture where the meal takes place.
[1] When dishes are served mostly in a single course, this is known in formal terms as service à la française; when dishes are served mostly in separate courses, this is called service à la russe.
[2] It came to be used perhaps because the food in a banquet serving had to be brought at speed from a remote kitchen – in the 1420 cookbook Du fait de cuisine the word "course" is used interchangeably with the word for serving.