膝
シツ, ひざ
knee, lap
JLPT0 G7 S15 F2320
As per
桼
# as described in
漆
(cut at intervals) +
肉
flesh → the *knee*, a joint that cuts the leg into two sections (compare
節
) → *lap* (formed when sitting with the knees together).
[Full Kanji Etymology List]