A peel is the covering of a fruit or vegetable. Some peels are thick and easy to remove, like an orange peel, while others might be more stubborn, like the thin peel on a potato.
When you remove an apple peel or the peel of an eggplant, you peel it. You can peel anything with a rind or skin, especially things you can eat, like shrimp and onions. There are non-edible things to peel, like stickers and old wallpaper too. You can also figuratively peel something: "I had to peel off my wet clothes and put dry ones on before I stopped shivering." The Latin root, pilare, means "to strip of hair."