coastline

noun

coast·​line ˈkōs(t)-ˌlīn 

1

: a line that forms the boundary between the land and the ocean or a lake

2

: the outline of a coast

Examples of coastline in a Sentence

The plane flew along the eastern coastline.

Recent Examples on the Web

More than half of New Jersey's coastline is still at risk of major flooding, the most severe classification through the National Oceanic and Atmospheric Administration (NOAA), amid a vicious coastal storm battering the East Coast. —Kate Plummer, MSNBC Newsweek, 14 Oct. 2025

The widespread collapse of reef ecosystems would be devastating for marine and human life— reefs help support fisheries, and protect coastlines from storm surges and rising sea levels. —Simmone Shah, Time, 12 Oct. 2025

Daniel returns to Italy, the land of his childhood, as a fixer in one of the world’s most luxurious hotels, located on the coastline of Positano. —Marta Balaga, Variety, 12 Oct. 2025

Oceans and coastlines contain the highest uncertainties of methane release, according to researchers. —Julia Jacobo, ABC News, 11 Oct. 2025

Word History

First Known Use

1856, in the meaning defined at sense 1

Rhymes for coastline

• affine
• airline
• align
• aline
• assign
• baseline
• beamline
• benign
• bloodline
• bovine
• byline
• canine

Kids Definition

coastline

noun

coast·​line ˈkōst-ˌlīn 

: the outline or shape of a coast