時差
じさ · jisa · JLPT N1 · noun
difference
⏰ 時 (time) + 差 (difference) = 時差, the time difference between places
Both kanji are common on their own: 時 means time and 差 means gap or difference. Put them together and you get the gap between two clocks, which is how far apart two places are in time.
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).