落差
luò chā · HSK 7
drop in elevation
🪂 落 fall + 差 difference = a falling difference: a drop in height, or a gap in pay or hopes
落 (luò) means to fall or drop; 差 (chā) means difference or gap. Together they name the literal drop between two elevations, and by extension any measured gap: between wages, between what you expected and what you got.
落 — grass radical 艹 + 洛 (water 氵 + 各)
Originally written with the grass radical 艹 over 洛, depicting leaves falling from plants. 洛 serves as the phonetic component (giving the luò sound) while 艹 supplies the meaning of vegetation. The sense extended from 'leaves falling' to the general meaning of falling, dropping, or settling down.
差 — 垂 (drooping) + 工 (work/tool)
Originally depicted a hand reaching down to grasp grain stalks of uneven length, suggesting discrepancy or unevenness. From this came the meaning 'difference' or 'to differ.' The reading chā specifically carries the sense of disparity, while other readings developed meanings like 'to dispatch' (chāi) and 'poor/lacking' (chà).