Cau"cus (?), n. [Etymology uncertain. Mr. J. H. Trumbull finds the origin of caucus in the N. A. Indian word cawcawwassough or caú 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.

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].

Cau"cus, v. i. [imp. & p. p. Caucused (?); p. pr. & vb. n. Caucusing.] To hold, or meet in, a caucus or caucuses.

• Appointment of presidential candidates within a party (United States).
  
• An area in the Eastern Europe (Republic of Armenia.)