Final Four

Final Four is a mainly American sports term that is commonly applied to the last four teams remaining in a playoff tournament. In other countries, where knock-out tournaments are more common than in the U.S., the last four stage of a knock-out competition is called the semi-finals.
The oldest, and most common, use of the term is in reference to the final four teams in the annual NCAA basketball tournament. These are the champions of the tournament's four regional brackets, and the only teams remaining on the tournament's final weekend. (The term has been applied retroactively to include the last four teams in tournaments from earlier years, when only two brackets existed.)