The noun caucus is a closed meeting of members from the same political party. The Iowa caucuses get a lot of attention during the presidential primary season.
Who knows how we got the noun caucus? One theory is that it comes from an Algonquin word that means an elder or leader of the tribe. Another theory is that the word comes from a social and political club in Boston in the 1700s that was perhaps named for the Greek word for drinking cup. However the word slipped into American English, today it refers to a closed political meeting, often used to choose party leaders.