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

The higher the seas, the greater the threat for California’s coastline. — Los Angeles Times, 8 Oct. 2026

Ethiopia lost its coastline when Eritrea became independent in 1993. — ABC News, 8 Oct. 2026

Mandatory evacuation orders have been issued for parts of Gulf and Okaloosa counties on the northwest Florida coastline. — Kate S. Petersen, CNN Money, 8 Oct. 2026

Life here happens on the beach, of course, and the coastline is the best vantage point for getting to know Naples. — Harriet Elton, Condé Nast Traveler, 8 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