1. In facsimile, the number of pixels per unit distance in the direction of scanning or recording. 2. In digital telegraphy, the number of pixels in the horizontal direction. 3. In raster-scanned television, the number of picture elements in a scan line. 4. In a computer monitor, the number of pixels per unit distance in the horizontal direction. Note: This value is inversely proportional to the dot pitch of the monitor.