Fragrance notes are the individual scents that make up a perfume or cologne. They are typically categorized into three layers: top notes, middle notes, and base notes. Top notes are the initial scents you smell when applying a fragrance, often light and fresh. Middle notes emerge after the top notes fade, providing the main character of the fragrance. Base notes are the deeper, richer scents that linger the longest, adding depth and warmth. Each layer of fragrance notes works together to create a harmonious scent experience. For example, a perfume might have citrus top notes, floral middle notes, and woody base notes. Understanding these notes helps consumers choose fragrances that suit their preferences and occasions.