A Mandarin is a small, loose-skinned, orange-yellow to deep orange-red citrus fruit. While many refer to mandarins as oranges, they are technically tangerines. All Clementines and Tangerines are Mandarins, but not all Mandarins are Clementines or Tangerines.
A Clementine is a deep red-orange, often seedless mandarin orange.
A Tangerine is a widely cultivated variety of mandarin orange having deep red-orange fruit with easily separated segments. Tangerines have seeds. A tangerine is smaller, less round, sweeter, and contains less acid than an orange. They have virtually the same nutritional values. Tangerines are smaller than oranges and the peel comes off easily.
Oranges are larger, as well as more tart and sweet than tangerines. Orange zest is the orange layer on the outside and the rind is the white underneath.
A Satsuma is a seedless mandarin orange native to Japan and the hardiest commercial citrus fruit.
Clementines look like small oranges: they are actually a cross between navel oranges and mandarin oranges. They are a great source of vitamin C and provide a natural sweet, honey-like flavor. They have shiny tight skins and make a great display as a centerpiece. Clementines are often confused with Satsumas, which have a looser skin.
Navel oranges are the most common type of oranges for eating. These sweet oranges are baseball sized, seedless, and sweet. The thick skins make these oranges easy to peel.
Blood oranges have a deep red color of the flesh that distinguishes them. They are smaller than navel oranges and are very sweet.
Valencia oranges are the classic orange for juicing. They have a thin skin and seeds. Valencia oranges are delicious to eat as a fruit, but more difficult to peel than navel oranges.
Seville and other sour oranges make great marmalade. They can be used to add acid when cooking, for cocktails, and in salad dressing. You can replace lemon or lime juice in recipes with the juice of a sour orange.