tux

n. 1. A kind of black jacket for semiformal evening dress made without tails, usually of black or dark blue color and having satin or grosgrain facing on the lapels; -- so named after a fashionable country club at Tuxedo Park, New York. [ U. S. ] [ RHUD ] [ Webster 1913 Suppl. +PJC ]

2. The complete semiformal evening suit, including the tuxedo jacket, matching trousers, and black bow tie, and usually including a cummerbund; -- the style of shirt worn with this suit varies, and the outfit may include a dickey. [ RHUD ] [ PJC ]