北米インディアンの長老を意味するネイティブ?インディアンの言葉からきている可能性がある。
caucus: "This noun is used throughout the United States, as a cant term for those meetings, which are held by the different political parties, for the purpose of agreeing upon candidates for office, or concerting any measure, which they intend to carry at the subsequent public, or town meetings." [John Pickering, "A Vocabulary, or Collection of Words and Phrases Which Have Been Supposed to be Peculiar to the United States of America," Boston, 1816]
The word caucus, and its derivative caucusing, are often used in Boston. The last answers much to what we stile parliamenteering or electioneering. All my repeated applications to different gentlemen have not furnished me with a satisfactory account of the origin of caucus. It seems to mean, a number of persons, whether more or less, met together to consult upon adopting and prosecuting some scheme of policy, for carrying a favorite point. [William Gordon, "History, Rise, Progress, and Establishment of the Independence of the United States of America," London, 1788]