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

Costa Blanca is stunning from dry land, but exploring by water offers an opportunity to see the coastline from a new perspective. —Liz Provencher, Travel + Leisure, 9 Jan. 2026

Russia, which stretches over half of the Arctic Ocean coastline, currently controls a majority of the region. —Connor Greene, Time, 9 Jan. 2026

Maritime defense autonomy By hosting CUAS capabilities on a surface drone, naval forces can project drone defense well beyond the coastline. —Georgina Jedikovska, Interesting Engineering, 9 Jan. 2026

Chris Lowe, director of the Shark Lab at California State University, Long Beach, said the rocky coastline near Lovers Point attracts sea lions, and seals also frequent offshore waters — both primary prey for great white sharks. —Ryan MacAsero, Mercury News, 8 Jan. 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
• byline
• canine

Kids Definition

coastline

noun

coast·​line ˈkōst-ˌlīn 

: the outline or shape of a coast