Multisample anti-aliasing (MSAA) is a graphics technique used to reduce the visual distortions known as aliasing, which can make edges appear jagged or pixelated. It works by taking multiple samples of a pixel and averaging the colors to create a smoother transition between edges. This helps to create a more visually appealing image, especially in 3D graphics. MSAA is commonly used in video games and computer graphics to enhance image quality without significantly impacting performance. By focusing on the edges of objects, it effectively minimizes the appearance of jagged lines while maintaining the overall detail of the scene.