Gradient combinations refer to the arrangement of colors that blend smoothly from one to another. They are often used in design, fashion, and art to create visually appealing transitions. In design, gradients can add depth and dimension to flat surfaces, while in fashion, they can be used to create striking outfits. They are a key element in various digital design tools like Adobe Photoshop and Illustrator, where they can be customized to fit specific design needs.