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

Nicknamed the Grand Strand, this 60-mile stretch of South Carolina coastline beckons travelers with mild temperatures, gentle ocean breezes and freedom from the crowds that pack the beaches during peak season. —Lisa A. Beach, USA Today, 13 Nov. 2025

Laguna Beach is the only city in the Golden State whose entire coastline is designated as a boating and fishing-free zone. —Acacia Gabriel, Travel + Leisure, 13 Nov. 2025

The countries that have a Baltic coastline today, excluding Russia, could agree to a new treaty requiring ships to meet certain standards of insurance and certification to be allowed to navigate the Baltic—for example, on grounds of ecological protection. —Jack Watling, Foreign Affairs, 11 Nov. 2025

The coastline offers crystal-clear waters, coral reefs and rugged mountains, while Aqaba Castle and the old seaport offer authentic historical textures. —Rafa Sales Ross, Variety, 10 Nov. 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