Pixel density refers to the number of pixels packed into a given area of a display, typically measured in pixels per inch (PPI). Higher pixel density results in sharper images and clearer text, making it an essential factor in the quality of screens found in devices like smartphones, tablets, and televisions. As pixel density increases, the human eye perceives finer details, enhancing the overall viewing experience. For instance, a display with a pixel density of 300 PPI will appear much crisper than one with only 100 PPI. This is particularly important for high-resolution content and virtual reality applications, where clarity is crucial.