from
The Collaborative International Dictionary of English v.0.48
Mileage \Mile"age\ (m[imac]l"[asl]j; 48), n.
1. An allowance for traveling expenses at a certain rate per
mile.
[1913 Webster]
2. Aggregate length or distance in miles; esp., the sum of
lengths of tracks or wires of a railroad company,
telegraph company, etc. [Written also {milage}.]
[1913 Webster]
3. The number of miles that a vehicle can travel after
consuming a certain quantity of fuel; in the United
States, usually expressed in units of miles per gallon;
as, smaller cars tend to get better mileage. It is
sometimes used as a nmeasure of the energy efficiency of a
vehicle.
[PJC]
4. Use, profit or advantage; as, he got a lot of mileage out
of one hit record.
[PJC]
{Constructive mileage}, a mileage allowed for journeys
supposed to be made, but not actually made. --Bartlett.
[1913 Webster]