Cocktail Dresses

  Cocktail dresses or cocktail gown is a woman's dress worn at cocktail parties, and semi-formal, or "black tie" occasions.
   
   The length of a cocktail dress varies depending on fashion and local custom. The length ranges from just above the knee to touching the ankle. When it is about 5 cm (2 inches) above the ankle it is called tea length and when it is almost touching the ankle it is called ballerina length, although ballerina length dresses usually fall into the evening gown category.
   In the mid-20th century, some couturiers began describing full-skirted cocktail gowns as "dancing costumes". These are suitable for formal dances but not for balls, or other white tie affairs, where ball gowns are worn.
   Christian Dior was the first to use the term "cocktail dress" to refer to early evening wear, in the late 1940s.