A tea-length dress is a dress whose hemline falls above the ankle and below the knee1. The modern tea-length dress is more likely to hit 3 to 4 inches above the ankle, in the mid-calf region.
A midi dress is any type of dress that rises above the ankles but falls below the knees, otherwise known as the mid-calf.
A "cocktail dress" is a knee-length or longer dress that is more formal than a sundress but less formal than a floor-length dress.
Tie or Bowtie accepted.
Doesn't necessarily need a tie with this.