means The instrument in a vehicle that measures and displays the total distance it has traveled.

from From the Greek 'hodos' (road, way) plus 'metron' (measure) — literally a 'road-measurer.' The ancient world already had such devices: Vitruvius and Hero of Alexandria described geared contraptions that dropped a pebble into a box at set intervals to tally distance. The English word arrives in the 18th century, stitched together from those Greek parts. That same 'hodos' hides in 'exodus' (the way out) and 'method' (a way of pursuing something).