also: みぎわせん
noun
shoreline; beach line
Technical or formal term for the line where land meets water, often used in geography, coastal engineering, or legal contexts.
この地図には汀線が正確に描かれている。
The shoreline is accurately drawn on this map.
海岸侵食によって汀線が後退している。
The shoreline is retreating due to coastal erosion.
海岸線 is a more common, everyday word for coastline or shoreline, while 汀線 is a technical term used in specialized fields.
Compound of 汀 (shore, water's edge) and 線 (line). The reading みぎわせん uses the kun'yomi of 汀 (みぎわ) combined with 線 (せん).