What is a primary caucus?

By visiting the listed site, the Fast Times Political Dictionary, we learned that a caucus is: "a private meeting of members of a political party to plan action or to select delegates for a nominating convention." Whereas, a primary is: "[an] election held to nominate a candidate for a particular party at a forthcoming election for public office." While these definitions were helpful, we also decided to search for a little more substantive information. We managed to turn up an article from Bella Online that helped clarify the difference between the two terms. During a primary, voters simply cast their ballot for a particular candidate. A caucus, on the other hand, is more of a party affair, sort of like a town hall meeting. Members gather and hear speeches and engage in discussion before voting for a candidate. The majority of candidates today are selected in primaries