The Cocktail Dress:  Worn at cocktail parties, and semi-formal occasions.  The length ranges from just above the knee to touching the ankle. Prior to the mid 20th century this type of dress was known as 'late afternoon'. When gentlemen are in business suits, ladies also wear dress suits or "good" afternoon dresses.  Christian Dior was the first to use the term "cocktail dress" to refer to early evening wear, in the late 1940s.