IPA: /ˈkoʊstlaɪn/
KK: /ˈkoʊstlaɪn/
The line where land meets the sea or a lake, often characterized by beaches, cliffs, or other natural features.
The coastline was beautiful, with sandy beaches and rocky cliffs.
Coastline → It is formed from "coast" (from Old French *coste*, meaning the side or edge of land) and "line" (from Latin *linea*, meaning a string or line). The word "coastline" refers to the line that defines the edge of the land along the sea.
Think of the 'edge' of the land ('coast') marked by a 'line' — that's what a coastline is.