(noun) conclusive encounter or contest. From poker, where at the termination of betting the hands of the players who are still in the game are laid on the table and compared to determine the winner. Also used metaphorically. Sometimes "throwdown" is used with this meaning.
"After several weeks of random threats and skirmishes, the two gangs met in the parking lot of Kresge's for a showdown."
by Anarcissie May 28, 2008