Pixels per inch (ppi)
In computers, pixels per inch (ppi) is a measure of the sharpness (the density of illuminated points) on a display screen . The dot pitch determines the absolute limit of the possible pixels per inch.
However, the displayed resolution of pixels (picture elements) that is set up for the display is usually not as fine as the dot pitch. The pixels per inch for a given picture resolution will differ based on the overall screen size since the same number of pixels are being spread out over a different space. The term "dots per inch" (dpi ), extended from the print medium, is sometimes used instead of pixels per inch.