An orange—specifically, the sweet orange—is the citrus Citrus × ​sinensis (Citrus sinensis (L.) Osbeck) and its fruit. It is the most commonly grown tree fruit in the world. Orange trees are widely cultivated in tropical and subtropical climates for the sweet fruit, which is peeled or cut (to avoid the bitter rind) and eaten whole, or processed to extract orange juice, and also for the fragrant peel.The fruit of Citrus sinensis is called sweet orange to distinguish it from Citrus aurantium, the bitter orange. Citrus Sinensis (L.) Osbeck is broken down into four groups with distinct characteristics: Common oranges, blood oranges, navels, and acidless oranges.Oranges, as with most citrus fruits, are a great source of vitamin C. The name "orange" applies primarily to the sweet orange, Citrus sinensis, which accounts for about 70% of world citrus production.