沿線
えんせん · ensen · JLPT N1 · noun
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沿 — water 氵 + 㕣 (marsh/valley) phonetic
沿 combines the water radical 氵 with 㕣, depicting a stream flowing through a small valley. Originally it meant to follow along the course of a river, and by extension came to mean 'to follow,' 'along,' or 'beside.' The 㕣 element also gives the sound.