Peaches and nectarines are related, but different fruits. They're almost genetically identical (that's why their flavor is similar), except for the fact that peaches have fuzzy skin and nectarines have smooth skin. Nectarines are often smaller than peaches, and they're typically juicier and tangier. You can use these two stone fruits interchangeably is most recipes. Learn more about the differences between nectarines and peaches.