The amount of service, use, or wear estimated by miles used or traveled, An allowance for travel expenses established at a specified rate per mile, An allowance or compensation for travel or conveyance reckoned by the mile; especially, payment allowed to a public functionary for the expenses of travel in the discharge of his duties according to the number of miles passed over_ as, the mileage of a sheriff, circuit judge, or member of Congress or of a legislature,