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

So, a single district across California’s entire upper tier and northern coastline made some sense. —David Mark, The Washington Examiner, 5 Sep. 2025

The film is an Arctic action-thriller inspired by the real-life Sirius Patrol, the Danish special forces unit charged with defending Greenland’s 8,700-mile frozen coastline. —Brent Lang, Variety, 4 Sep. 2025

Photos show several of the animals breaching the surface near the rocky coastline. —Brendan Rascius, Miami Herald, 4 Sep. 2025

But the Romans repeatedly defeated the Carthaginians, and by 146 BCE the great city of Carthage was sacked and destroyed, leaving the Romans in control of a vast swath of the Mediterranean coastline, including many territories that had once been under Carthaginian control. —Literary Hub, 3 Sep. 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