Orange peel is the outer colored layer of the skin of the orange, which, like all hesperide fruits, is thick, bumpy, and studded with oil-producing glands. Commonly used in both cooking and baking, orange peel can also be candied, used as a garnish, or expressed over the top of a cocktail to provide an aromatic punch to the drink. If the orange peel is cut into small pieces, especially with a citrus zester, it is usually referred to as zest.
An orange spiral is a long twist of orange peel, typically cut using a channel knife. Orange spirals are almost always used as a garnish, and can be hung from the rim of a cocktail glass in a decorative fashion.
Orange oil is made up of almost 90% limonene, a monoterpene aromachemical with a typical orange aroma. There are also small amounts of Bergaptene and Myrcene as well.