Source : Webster's Revised Unabridged Dictionary (1913)

Conclave \Con"clave\ (? or ?; 277), n. [F., fr. L. conclave a
   room that may locked up; con- + clavis key. See {Clavicle}.]
   1. The set of apartments within which the cardinals of the
      Roman Catholic Church are continuously secluded while
      engaged in choosing a pope.

   2. The body of cardinals shut up in the conclave for the
      election of a pope; hence, the body of cardinals.

            It was said a cardinal, by reason of his apparent
            likelihood to step into St. Peter's chair, that in
            two conclaves he went in pope and came out again
            cardinal.                             --South.

   3. A private meeting; a close or secret assembly.

            The verdicts pronounced by this conclave (Johnson's
            Club) on new books, were speedily known over all
            London.                               --Macaulay.

   {To be in conclave}, to be engaged in a secret meeting; --
      said of several, or a considerable number of, persons.

Source : WordNet®

conclave
     n : a confidential or secret meeting