Quince (Cydonia vulgaris) refers to a fruit that is related to the pear and grown in the Mediterranean, the Middle East and the United States. This fruit resembles a lumpy pear without the neck. The fruit is yellow when ripe with flesh that is various shades of yellow.

This yellow-skinned fruit looks and tastes like a Cross between an apple and a pear. Its texture and flavor make it better cooked than raw. Its high pectin content make it ideal for use in jams, jellies, and preserve

Quinces are seasonal and can be found in autumn to early winter. Since quinces are not frequent ingredients in most American cooking, one may have to look for them in Middle Eastern or Hispanic food markets.

This pleasantly tart fruit needs to be cooked before eating. Quinces are high in pectin, so they're commonly used to make jams and jellies. Some cooks simply bake them like apples. When fully ripe, the quince has a wonderful perfume. It belongs to the apple family with much the same shape as an apple but a furry skin.
Other definition:
When fully ripe, the quince has a wonderful perfume. It belongs to the apple family with much the same shape as an apple but a furry skin. Quince should not be eaten raw because it is very hard and bitter but it makes excellent preserves, especially marmalade.
List of books: Quince