During Victorian times, it became popular for people to put on their finest clothing and gather for social events, including dinners or parties. The dress codes for these events eventually broke down into two types of evening wear: white tie and black tie. Even though etiquette has relaxed over the years, there are still enough events that demand either black tie or white tie standards.
Black tie events today are primarily reserved for private entertainments, formal public events and major productions or performances in the cultural arts. Some of these events might include an opening season of the opera or ballet, a political fundraising dinner or country club dances.
A proper black-tie ensemble consists of a black or midnight blue dinner jacket, either single or double-breasted. This is paired with trousers that match the jacket. A white shirt with a collar with French cuffs for cufflinks is worn. A black cummerbund or waistcoat can be worn, but these are falling out of style in recent years. A black bow tie and polished leather shoes finish off the look. For summer black tie affairs or for formal events in a tropical climate, a man may wear a white jacket paired with a black cummerbund. Women have it a little easier, in that they can wear a nice cocktail dress.
White tie dress standards are becoming more rare as the black tie ensemble is essentially considered appropriate for most formal events. However, as the most formal dress code, there are still several occasions for white tie. General rules include that it can only be worn after 6:00 p.m. and events often calling for a white tie standard of dress might include state dinners, balls at universities, cotillions, formal weddings, major ceremonies and events including a royal family.
A white tie ensemble consists of a black dress coat with tails, matching black trousers with a satin stripe, a white stiff-fronted shirt, a white waistcoat and white bow tie and black patent leather shoes. The coat is cut so that it should not be buttoned when worn. It is acceptable to wear medals, sashes and other decorations for those with royal, political or military honors. Women are expected to wear floor-length evening gowns.
If you are invited to a formal event, it is proper etiquette for the invitation to say whether or not the event is black tie or white tie.
Some may argue that the term "casual dress" is widely open to interpretation and in some ways they're right. What's considered casual and appropriate by today's standards has evolved significantly from even a few decades ago, still, there are few fashion tips that transcend the ages when it comes to keeping things cool, casual and composed.