An alpha channel is a component of digital images that represents transparency. It allows for varying levels of opacity, enabling parts of an image to be fully transparent, partially transparent, or completely opaque. This feature is essential in graphic design and video editing, as it helps blend images seamlessly into backgrounds. In formats like PNG and TIFF, the alpha channel is an additional layer alongside the standard color channels (red, green, and blue). By manipulating the alpha channel, artists can create effects such as shadows, glows, and smooth transitions, enhancing the visual quality of their work.