沿
yán · HSK 6
along
🧵 yán ~ yarn: a thread running along the edge
The water radical 氵 shows a river. Water follows along the bank, and yán sounds like yarn trailing along a seam.
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.