落下
luòxià · HSK 7
fall/lag behind
🍂 落 (fall) + 下 (down) = drop downward; also fall/lag behind a group
Two characters stack the same idea: 落 means to fall or drop, 下 means down or below. Together they mean falling downward, and by extension lagging or trailing behind others. 下 also marks the downward direction in many compounds.
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.
下 — horizontal line 一 + mark below
下 is an indicative character: a long horizontal line represents a reference level, and a shorter stroke placed beneath it points to the area below. The original meaning 'below, down' comes directly from this spatial diagram, and it later extended to verbs like 'descend' and 'lower'.