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