The term 'Smooth-skinned Fruit' refers to three fruits: Plums, Grapes, and Nectarines. Plums are small, round fruits with a smooth, purple skin and a sweet, juicy flesh. Grapes are small, round fruits with a smooth, green or purple skin and a sweet, juicy flesh. Nectarines are similar to peaches, but have a smooth, yellow or red skin and a sweet, juicy flesh. All three of these fruits are popular in many cultures and are often eaten fresh or used in cooking.