dress code是black suit, 應穿什麼?

Black tie is a dress code for formal evening events, whose primary component is the dinner jacket. The jacket and matching trousers are typically called a tuxedo in the United States and Canada; they are known in Continental Europe and Japan as smoking, a pseudo-Anglicism from earlier smoking jacket.
Black tie is today worn at a wide variety of functions, and the corresponding female attire can range from a short cocktail dress to a long Evening gown, depending on fashion, local custom and the hour at which the function takes place.
The waist sash, called a cummerbund, was borrowed after World War I from military dress in British India. Black waistcoats are often worn instead of cummerbunds. There is also an older tradition carried over from white tie, which has largely died out, of wearing a white waistcoat with a dinner jacket when ladies are present. This is an option seen only on the most dress tradition conscious dandy today.

Black suit :

For men : It's black suit 黑色西裝 with tie, bow tie. Dressing formal, tie should not be Mickey mouse, red roses ......

For ladies : It's black or dark evening dress, formal dress, such as 吊帶晚禮長裙.