屈折
くっせつ · kussetsu · JLPT N1 · noun
refraction
折 — hand 扌 + axe 斤
Originally written as 折 with a hand (扌) breaking or chopping something with an axe (斤), depicting the act of snapping or cutting in two. The core meaning 'to break, snap, fold' extends metaphorically to 'bend,' 'turn back,' and 'discount' (as in reducing a price by breaking off part).