The term means the common basis of the everyday diet in a place. Potatoes and rice are the most usual examples, but bread is not a staple food because it is a manufactured food which cannot be stored. Of course, it can always be made, since wheat is a staple food. Fruit is not a staple because it usually grows at a certain time of year. Meat is not a staple because it may not be available, or is expensive to buy. Green vegetables may be a staple in some countries, but not others. Foods which need special facilities, such as refrigeration are not staple foods.
Here are some examples of staple foods: