Sankaku Channel/petticoat

A women's undergarment consisting of material draped from the waist and worn under a skirt or dress. It has two purposes: to keep the skirt from riding up (like a slip) and to add fullness to the skirt. For the latter reason, petticoats are often heavily ruffled and comprise multiple layers. Wearing a petticoat low enough for the lace edge to be visible is a common feature of lolita fashion.

See also