The Collaborative International Dictionary of English v.0.48:

Mile \Mile\ (m[imac]l), n. [AS. m[imac]l, fr. L. millia, milia;
   pl. of mille a thousand, i. e., milia passuum a thousand
   paces. Cf. Mill the tenth of a cent, Million.]
   A certain measure of distance, being equivalent in England
   and the United States to 320 poles or rods, or 5,280 feet.
   [1913 Webster]

   Note: The distance called a mile varies greatly in different
         countries. Its length in yards is, in Norway, 12,182;
         in Brunswick, 11,816; in Sweden, 11,660; in Hungary,
         9,139; in Switzerland, 8,548; in Austria, 8,297; in
         Prussia, 8,238; in Poland, 8,100; in Italy, 2,025; in
         England and the United States, 1,760; in Spain, 1,552;
         in the Netherlands, 1,094.
         [1913 Webster]

   Geographical mile or Nautical mile, one sixtieth of a
      degree of a great circle of the earth, or 6080.27 feet.

   Mile run. Same as Train mile. See under Train.

   Roman mile, a thousand paces, equal to 1,614 yards English
      measure.

   Statute mile, a mile conforming to statute, that is, in
      England and the United States, a mile of 5,280 feet, as
      distinguished from any other mile.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Roman mile
    n 1: an ancient Roman unit of length equivalent to 1620 yards
         [syn: mile, Roman mile]