NOUN (1)

1. a closed political meeting;


VERB (1)

1. meet to select a candidate or promote a policy;

The Collaborative International Dictionary of English v.0.48:

Caucus \Cau"cus\, n. [Etymology uncertain. Mr. J. H. Trumbull
   finds the origin of caucus in the N. A. Indian word
   cawcawwassough or ca['u] cau-as'u one who urges or pushes on,
   a promoter. See citation for an early use of the word
   caucus.]
   A meeting, especially a preliminary meeting, of persons
   belonging to a party, to nominate candidates for public
   office, or to select delegates to a nominating convention, or
   to confer regarding measures of party policy; a political
   primary meeting.
   [1913 Webster]

         This day learned that the caucus club meets, at certain
         times, in the garret of Tom Dawes, the adjutant of the
         Boston regiment.                         --John Adams's
                                                  Diary [Feb.,
                                                  1763].
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Caucus \Cau"cus\, v. i. [imp. & p. p. Caucused; p. pr. & vb.
   n. Caucusing.]
   To hold, or meet in, a caucus or caucuses.
   [1913 Webster]

WordNet (r) 3.0 (2006):

caucus
    n 1: a closed political meeting
    v 1: meet to select a candidate or promote a policy

Moby Thesaurus II by Grady Ward, 1.0:

93 Moby Thesaurus words for "caucus":
   assemblee, assembly, assignation, at home, ball, brawl,
   breakaway group, by-election, camp, closed primary, colloquium,
   commission, committee, conclave, concourse, congregation, congress,
   congressional caucus, congressional election, contested election,
   conventicle, convention, convocation, council, dance, date, diet,
   direct primary, division, eisteddfod, election, ethnic group,
   faction, festivity, fete, forgathering, forum, gathering,
   general election, gerrymander, get-together, housewarming,
   interest, interest group, levee, mandatory primary, meet, meeting,
   minority group, nonpartisan primary, offshoot, open primary,
   optional primary, packed caucus, panel, partisan election, party,
   plenum, political party, politicize, preference primary,
   presidential election, presidential preference primary,
   presidential primary, pressure group, primary, primary election,
   prom, quorum, rally, reception, referendum, rendezvous, runoff,
   runoff election, runoff primary, seance, secret caucus, sect,
   session, shindig, side, silent majority, sit-in, sitting, soiree,
   splinter, splinter group, symposium, synod, turnout,
   vocal minority, wing