The smallest unit of any digitized image or sound, the size and frequency of which are determined by the sampling rate of the digitizing device. In scanning of images, sampling rate is measured in pixels per inch, the size being determined by the size of scanning beam and the amount of space it moves as it captures the image. In the digitizing of audio, the sampling rate is measured in kilohertz, or the number of discrete "bursts" of sound occurring every second.