Being one of the most cultivated fruits in the world, Malus domestica or the apple tree, originates from central Asia. The worlds leading producer of apples is China with the United States following in second place. The apple is a pome (fleshy) fruit, in which the ripened ovary and surrounding tissue both become fleshy and edible. When harvested, apples are usually roundish, 5–10 cm (2–4 inches) in diameter, and some shade of red, green, or yellow in colour; they vary in size, shape, and acidity depending on the variety.
Apple varieties, of which there are thousands, fall into three broad classes: (1) cider varieties; (2) cooking varieties; and (3) dessert varieties, which differ widely but tend to emphasize colour, size, aroma, smoothness, and perhaps crispness and tang.