La soirée means the evening; 'black tie optional' are English words.
Yes and no. You wear a black tie to formal events.
Yes, Because it's OPTIONAL. And Burgundy is close to black with it being lighter.
Suit and tie
In a word, no! If you choose not to wear formal attire to a "black tie optional event" the expectation is that you will wear a dark suit with a necktie if a guy or a cocktail dress if a woman.
Either a formal gown or a cocktail dress.
It is either black tie or optional, but generally it is not both. On the safe side the woman can wear a pair of nice slacks with a fancy top and some dainty jewelry; a dress (any color, but white) such as a cocktail dress (in black or other colors) with a little jewelry and some nice shoes.
One wears a formal suit with white shirt and black tie.
No, you may not wear a dark blue shirt and black slacks to a black-tie optional event. Even though the black tie is "optional", it still indicates that guests should wear very formal clothing. It is likely that many of the guests will be wearing tuxedos, but a dark colored suit preferably black) with a crisp white shirt and a darker tie are still appropriate. At the bare minimum, you might be able to blend in without the jacket, but it is best to wear the full suit. Ultra formal events, which are rare in America, are "white tie formal". This includes things like the Inaugural ball for the President. Just below this is "black tie formal", which includes things like the Oscars. "Black tie optional" is just below this distinction, so these events are still considered very formal. Hence, the need for the dark suit if one cannot wear the tuxedo. For more information see this wiki post: http://wiki.answers.com/Q/What_does_Black_attire_mean
White bow ties are worn with morning coats of varying colors. Evening wear requires a black coat and black tie. A man's evening wear is meant to keep him from clashing with his partner's gown, so black and white are preferred.
'Black tie' means that you have to wear a tux (US) or a dinner jacket (UK). Any color is fine, but black is recommended for gentlemen. If you were to wear a white jacket, then black pants are appropriate. Shoes should be pumps or patent leather oxfords (closed laces).
Women's black tie must not always be a long gown; indeed, several fashion authorities consider a "short, dressy cocktail dress" acceptable. http://www.blacktieguide.com/Supplemental/Ladies.htm
black bow tie