A V-shaped or U-shaped neckline which goes down to below the breasts.
Note that despite it being called a "neckline", starting at neck level is not necessary; the word simply refers to the topmost edge of the garment. Shirts & dresses which exist only as high as cleavage level can still count.
This should not be used for garments which are closed above the breasts (Strings and laces above the breasts are fine), and should only be used for unzipped or unbuttoned garments if they are consistently worn in this manner by an established character.
