over-kneehighs
オーバーニー オーバーニーソックス オーバーニーハイ ニーハイソックス ストッキング ブルマニーソ 过膝袜
Socks or stockings that end just above the knee. In comparison to regular thighhighs, they are shorter and leave a larger gap between the legwear and the skirt or dress in cases of zettai ryouiki.
Judge length based on the distance from the top of the legwear and the knee, not the size of the gap. Combinations of certain clothing with full thighhighs can also produce a sizable area of exposed skin.
See Danbooru post #86570 for reference, read the translation notes.