Definitions
Screen size & display glossary.
Consistent terminology makes screen comparisons easier to understand, calculate, and cite.
- Active display
- The part of a screen that produces the visible image, excluding the surrounding bezel.
- Aspect ratio
- The proportional relationship between a screen’s long and short sides, such as 16:9, 16:10, or 4:3.
- Bezel
- The frame surrounding the active display. It affects overall product size but is not included in the screen diagonal.
- Diagonal
- The straight-line distance from one corner of the active display to the opposite corner.
- Display resolution
- The native horizontal and vertical pixel count, commonly written as width × height.
- Letterboxing
- Horizontal bars shown when content is wider in shape than the screen.
- Nominal size
- A rounded size-class label used for product naming or marketing rather than an exact physical measurement.
- Pixel
- The smallest individually addressable picture element in a digital display.
- Pixel density (PPI)
- The number of pixels per physical inch, calculated from resolution and diagonal.
- Pixel pitch
- The physical distance between neighboring pixel centers, often expressed in millimetres.
- Screen area
- The physical surface of the active display, approximated as width multiplied by height for a rectangle.
- Screen-to-body ratio
- An estimate of how much of a device’s front face is occupied by its display.
- Standard rectangle
- The full rectangular envelope used to measure a rounded-corner display; actual viewable area may be smaller.
- Pillarboxing
- Vertical bars shown when content is narrower in shape than the screen.
- Viewport
- The software-defined area available for page content; it is not the same as native resolution or physical screen size.