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

Although not a major concern, some minor coastal flooding and beach erosion are possible along the coastline as well. —Matthew Villafane, CBS News, 25 Jan. 2026

Multiple fish have been spotted along the Southern California coastline, Mexico and in Taiwan, approximately five in total since 2023. —Amaris Encinas, USA Today, 24 Jan. 2026

In the opposite direction, there's an eight-mile walking and running track that hugs the coastline and is perfect for sunset strolls. —Selina Denman, Condé Nast Traveler, 23 Jan. 2026

Modern cities with sleek high-rises, a pristine coastline that attracts tourists, and a state-of-the-art port that juts into the Mediterranean. —Julia Frankel, Fortune, 23 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