What is meant by the term distance miles?

If your flight ticket was not issued by Lufthansa (220), SWISS (724), Austrian Airlines (257), Brussels Airlines (082) or Eurowings (104), the distance miles reflect the actual distance flown on your route. They form the basis for the number of miles credited for long-haul flights. The distance miles are multiplied by a percentage factor that varies depending on the booking class. For intercontinental Business Class trips with Lufthansa, for example, the number of distance miles is doubled. For equivalent flights in First Class, the total number of distance miles is tripled.