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

Great Lakes and coastlines, according to a preprint in bioRxiv. — Devika Rao, TheWeek, 15 Oct. 2026

Surf was even less accessible, dependent on coastline and a lucky swell. — Robb Report Studio, Robb Report, 15 Oct. 2026

Valentine was found unresponsive near the rocky coastline at the south end of Sand Dollar Beach, according to the news release. — Joan Lynch, Sacbee.com, 15 Oct. 2026

Iran rejects that route and demands that all vessels use a northern passage close to its own coastline, seeking permission from its military. — Frank Andrews, CBS News, 13 Oct. 2026

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
• brucine
• byline

Kids Definition

coastline

noun

coast·​line ˈkōst-ˌlīn 

: the outline or shape of a coast