Perfumes are composed of different layers of scents, called fragrance notes. These notes are divided into three categories:

Top notes: These are the first scents that you smell when you spray a perfume. They are usually fresh, citrusy, fruity, or floral, and they evaporate quickly.
Middle notes: These are the scents that emerge after the top notes fade. They are usually more complex, spicy, woody, or oriental, and they last longer.
Base notes: These are the scents that linger on your skin after the middle notes disappear. They are usually rich, musky, earthy, or sweet, and they last the longest.