1) Close-fitting evening wear 2) Formal wear 3) Project Runway creation 4) Semiformal wear 
A cocktail dress or cocktail gown is a woman`s dress worn at cocktail parties and semi-formal or `black tie` occasions. Historically the length of a cocktail dress is long, often 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, al......
A cocktail dress is a woman's formal dress, not quite as formal as a ball gown and usually shorter, designed to be worn in early evening, such as at cocktail parties.
[n] - a dress suitable for formal occasions
noun a dress suitable for formal occasions