1) Formal wear 
White tie (or full dress, evening dress, full evening dress; slang top hat and tails or white tie and tails, tailsuit, tails) is the most formal evening dress code in Western fashion. It is worn to ceremonial occasions such as state dinners in some countries, as well as to very formal balls and evening weddings. The chief components for men are: W...
[n] - bow tie worn as part of a man`s formal evening dress[adj] - requiring white ties and tailcoats for men
noun bow tie worn as part of a man`s formal evening dress adjective requiring white ties and tailcoats for men; `a white-tie occasion`