A process of encoding information using fewer bits, that is, 0 or 1, than an original representation, to reduce file size – typically using mathematical formulas to remove repeated data, combine related data or simplify data (for example, a line segment can be represented by the position of the end points instead of every dot on it). Common examples include:

  • .zip files, which can contain one or more files or folders that have been compressed
  • .jpg files in digital photography are produced by processing complete (lossless) data from a camera’s sensor through compressing (looking for redundant/unnecessary data) into a smaller file size
  • .mp3 files for audio, which compress an original audio source to reduce the file size significantly but still sound like an exact copy of the original.