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):

mile
    n 1: a unit of length equal to 1,760 yards or 5,280 feet;
         exactly 1609.344 meters [syn: mile, statute mile, stat
         mi, land mile, international mile, mi]
    2: a unit of length used in navigation; exactly 1,852 meters;
       historically based on the distance spanned by one minute of
       arc in latitude [syn: nautical mile, mile, mi, naut
       mi, knot, international nautical mile, air mile]
    3: a large distance; "he missed by a mile"
    4: a former British unit of length once used in navigation;
       equivalent to 6,000 feet (1828.8 meters) [syn: sea mile,
       mile]
    5: a former British unit of length equivalent to 6,080 feet
       (1,853.184 meters); 800 feet longer than a statute mile [syn:
       nautical mile, naut mi, mile, mi, geographical
       mile, Admiralty mile]
    6: an ancient Roman unit of length equivalent to 1620 yards
       [syn: mile, Roman mile]
    7: a Swedish unit of length equivalent to 10 km [syn: mile,
       mil, Swedish mile]
    8: a footrace extending one mile; "he holds the record in the
       mile"