Boycott obligation for formal dress

WordNet Word definitions in WordNet
n. semiformal evening dress for men [syn: dinner jacket , tux , tuxedo ] a black bow tie worn with a dinner jacket

Wikipedia Word definitions in Wikipedia
Black tie , sometimes known by its French name cravate noir , is a semi-formal dress code for evening events and social functions derived from British and American costume conventions of the 19th century. Traditionally worn only for events after 6 p.m., ...

Wiktionary Word definitions in Wiktionary
n. 1 evening dress; a standard of dress which is less formal than white tie, consisting of black dinner jacket or tuxedo jacket, and matching trousers, white shirt and black bow tie or, possibly, military dress or national costume. 2 (&lit black tie English) ...