The Collaborative International Dictionary of English v.0.48:

League \League\ (l[=e]g), 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.
      [1913 Webster]

   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.
         [1913 Webster]

   2. A stone erected near a public road to mark the distance of
      a league. [Obs.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

League \League\ (l[=e]g), n. [F. ligue, LL. liga, fr. L. ligare
   to bind; cf. Sp. liga. Cf. Ally a confederate, Ligature.]
   1. An alliance or combination of two or more nations,
      parties, organizations, 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.
      [1913 Webster]

            And let there be
            'Twixt us and them no league, nor amity. --Denham.
      [1913 Webster]

   2. Specifically: (Sports) An association of sports teams that
      establishes rules of play, decides questions of membership
      in the league, and organizes matches between the member
      teams. In some cases a sports league is called a
      conference, as in the National Football Conference.
      [PJC]

   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.
         [1913 Webster]

   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; cooperation.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

WordNet (r) 3.0 (2006):

league
    n 1: an association of sports teams that organizes matches for
         its members [syn: league, 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)
    v 1: unite to form a league

Moby Thesaurus II by Grady Ward, 1.0:

295 Moby Thesaurus words for "league":
   Anschluss, Bund, NATO, Rochdale cooperative, SEATO, accouple,
   accumulate, act in concert, act together, addition, affiliate,
   affiliate with, affiliation, agglomeration, agglutinate,
   aggregation, agreement, alignment, alliance, ally, amalgamate,
   amalgamation, amass, anschluss, articulate, assemblage, assemble,
   assimilation, associate, association, axis, band, band together,
   be in cahoots, be in league, blend, blending, bloc, body, bond,
   bracket, bridge, bridge over, brotherhood, bunch, bunch up, cabal,
   cahoots, capitulation, cartel, category, cement, cement a union,
   centralization, centralize, chain, circuit, clap together, clot,
   club, club together, cluster, coact, coadunation, coalesce,
   coalescence, coalition, collaborate, colleagueship, collect,
   college, collegialism, collegiality, collude, combination, combine,
   combo, come into, come together, common market, composition,
   comprise, comradeship, concatenate, concert, concord, concordat,
   concur, confederacy, confederate, confederation, conference,
   confraternity, congeries, conglobulate, conglomeration, congregate,
   conjoin, conjugate, conjugation, conjunction, connect, consociate,
   consolidate, consolidation, conspiracy, conspire,
   consumer cooperative, convention, converge, cooperate, cooperative,
   cooperative society, copartnership, copartnery, copulate, corps,
   council, couple, cover, credit union, creep in, crowd,
   customs union, date, division, do business with,
   economic community, ecumenism, embodiment, embrace, encompass,
   encompassment, enlist, enosis, enroll, entente, entente cordiale,
   enter, federalization, federalize, federate, federation,
   fellowship, flock together, flow together, forgather, fraternalism,
   fraternity, fraternization, free trade area, freemasonry, fuse,
   fusion, gang, gang around, gang up, gather, gather around,
   get heads together, get into, get together, glue, go in partners,
   go in partnership, go into, go partners, grade, group, grouping,
   guild, hang together, harmonize, herd together, hive,
   hold together, hook up, hook up with, hookup, horde, huddle,
   include, inclusion, incorporation, integration,
   international agreement, join, join forces, join fortunes with,
   join in, join together, join up, join up with, join with, junction,
   junta, keep together, knot, lay together, league together,
   league with, link, loop, lump together, machine, make common cause,
   marriage, marry, marshal, mass, meet, meld, melding, merge, merger,
   mill, mob, mobilize, muster, mutual-defense treaty,
   nonaggression pact, order, organize, package, package deal,
   paction, pair, pair off, partner, partnership, piece together,
   pigeonhole, play ball, political machine, pull together,
   put heads together, put together, rally, rally around, reciprocate,
   rendezvous, ring, seethe, sign on, sign up, sneak in, society,
   sodality, solder, solidification, sorority, span, splice,
   stand together, stand up with, stick together, stream, surge,
   swarm, syncretism, syndication, syneresis, synthesis, take in,
   take out membership, take up membership, tape, team up,
   team up with, team with, throng, throw in together, throw in with,
   tie, tie in, tie in with, tie up, tie up with, tie-in, tie-up,
   tier, treaty, unification, unify, union, unionize, unite,
   unite efforts, unite with, wed, wedding, weld, wheel,
   work together, yoke



Easton's 1897 Bible Dictionary:

League
   a treaty or confederacy. The Jews were forbidden to enter into
   an alliance of any kind (1) with the Canaanites (Ex. 23:32, 33;
   34:12-16); (2) with the Amalekites (Ex. 17:8, 14; Deut.
   25:17-19); (3) with the Moabites and Ammonites (Deut. 2:9, 19).
   Treaties were permitted to be entered into with all other
   nations. Thus David maintained friendly intercourse with the
   kings of Tyre and Hamath, and Solomon with the kings of Tyre and
   Egypt.


Bouvier's Law Dictionary, Revised 6th Ed (1856):

LEAGUE, measure. A league is a measure of length, which consists of three
geographical miles. The jurisdiction of the United States extends into the
sea a marine league. See Acts of Congress of June 5, 1794; 1 Story's L. U.
S. 352; and April 20, 1818, 3 Story's L. U. S. 1694; 1 Wait's State Papers,
195. Vide Cannon Shot.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

LEAGUE, crim. law, contracts. In criminal law, a league is a conspiracy to
do an unlawful act. The term is but little used.
     2. In contracts it is applied to agreements between states. Leagues
between states are of several kinds. 1st. Leagues offensive and defensive,
by which two or more nations agree not only to defend each other, but to
carry on war against their common enemies. 2d. Defensive, but not offensive,
obliging each to defend the other against any foreign invasion. 3d. Leagues
of simple amity, by which one contracts not to invade, injure, or offend the
other; this usually includes the liberty of mutual commerce and trade, and
the safe guard of merchants and traders in each others dominion. Bac. Ab.
Prerogative, D 4. Vide Confederacy; Conspiracy; Peace; Truce; War.