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

In addition to preserving natural ecosystems and the sustainable fisheries that depend on them, reefs may help to protect coastlines from storms and floods, which will become ever more urgent as climate change and rising sea levels give rise to more dangerous storms. —JSTOR Daily, 31 Oct. 2025

For decades, the Algarve has been beloved for its endless sunny days and dramatic coastlines with its picturesque beaches, craggy cliffs, and hidden caves. —Chadner Navarro, Vogue, 30 Oct. 2025

Now, with a bevvy of warships off his coastline, the resistance could be different. —Cybele Mayes-Osterman, USA Today, 30 Oct. 2025

Perched high above the Florida coastline at The Estates at Acqualina in Sunny Isles Beach, this four-bedroom, five-and-a-half-bath condo translates Bugatti’s design language into livable art. —Abby Montanez, Robb Report, 29 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