Source : Webster's Revised Unabridged Dictionary (1913)

League \League\, n. [Cf. OE. legue, lieue, a measure of length,
   F. lieue, Pr. lega, legua, It. & LL. lega, Sp. legua, Pg.
   legoa, legua; all fr. LL. leuca, of Celtic origin: cf. Arm.
   leo, lev (perh. from French), Ir. leige (perh. from English);
   also Ir. & Gael. leac a flag, a broad, flat stone, W. llech,
   -- such stones having perh. served as a sort of milestone
   (cf. {Cromlech}).]
   1. A measure of length or distance, varying in different
      countries from about 2.4 to 4.6 English statute miles of
      5.280 feet each, and used (as a land measure) chiefly on
      the continent of Europe, and in the Spanish parts of
      America. The marine league of England and the United
      States is equal to three marine, or geographical, miles of
      6080 feet each.

   Note: The English land league is equal to three English
         statute miles. The Spanish and French leagues vary in
         each country according to usage and the kind of
         measurement to which they are applied. The Dutch and
         German leagues contain about four geographical miles,
         or about 4.6 English statute miles.

   2. A stone erected near a public road to mark the distance of
      a league. [Obs.]

League \League\, n. [F. ligue, LL. liga, fr. L. ligare to bind;
   cf. Sp. liga. Cf. {Ally} a confederate, {Ligature}.]
   An alliance or combination of two or more nations, parties,
   or persons, for the accomplishment of a purpose which
   requires a continued course of action, as for mutual defense,
   or for furtherance of commercial, religious, or political
   interests, etc.

         And let there be 'Twixt us and them no league, nor
         amity.                                   --Denham.

   Note: A league may be offensive or defensive, or both;
         offensive, when the parties agree to unite in attacking
         a common enemy; defensive, when they agree to a mutual
         defense of each other against an enemy.

   {The Holy League}, an alliance of Roman Catholics formed in
      1576 by influence of the Duke of Guise for the exclusion
      of Protestants from the throne of France.

   {Solemn League and Covenant}. See {Covenant},2.

   {The land league}, an association, organized in Dublin in
      1879, to promote the interests of the Irish tenantry, its
      avowed objects being to secure fixity of tenure fair rent,
      and free sale of the tenants' interest. It was declared
      illegal by Parliament, but vigorous prosecutions have
      failed to suppress it.

   Syn: Alliance; confederacy; confederation; coalition;
        combination; compact; co["o]peration.

League \League\, v. i. [imp. & p. p. {Leagued}; p. pr. & vb. n.
   {Leaguing}.] [Cf. F. se liguer. See 2d {League}.]
   To unite in a league or confederacy; to combine for mutual
   support; to confederate. --South.

League \League\, v. t.
   To join in a league; to cause to combine for a joint purpose;
   to combine; to unite; as, common interests will league
   heterogeneous elements.

Source : WordNet®

league
     v : unite to form a league

league
     n 1: an association of sports teams that organizes matches for
          its members [syn: {conference}]
     2: an association of states or organizations or individuals for
        common action
     3: an obsolete unit of distance of variable length (usually 3
        miles)