A miliarium (Classical Latin: [miːllɪˈaːrɪ.ũː ˈau̯rɛ.ũː]) was a cylindrical, oval or parallelepiped column placed on the edge of Roman roads to mark the distances every thousand passus (double Roman steps), that is, every mile. Today, this is equivalent to a distance of approximately 1480 meters. The stone known as the Milliarium Aureum was the point used to indicate the distance to Rome from any point in the Roman Empire.
These physical markers of distance corresponded to the abstract route descriptions found in Roman itinerarium, which were text-based lists of cities, stops, and the distances between them.