The hemline of a wedding dress is its lower edge.
Ankle Length - reaches the ankle
Asymmetrical - a hemline that is cut on the diagonal, not parallel with the floor.
Floor Length - Reaches the floor
Knee Length - Reaches the middle of the knee
Short / Mini - Higher than the knee, with the hem often at the mid-thigh or higher.
Tea-length - hemmed at the shin, inbetween knee-length and ankle length