Pronunciation: (tuk-sē'dō),[key] —n., —pl.-dos. 1. Also calleddinner jacket. a man's jacket for semiformal evening dress, traditionally of black or dark-blue color and characteristically having satin or grosgrain facing on the lapels.
2. the complete semiformal outfit, including this jacket, dark trousers, often with silk stripes down the sides, a bow tie, and usually a cummerbund.