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

Tucked between Gainesville and Ocala in north-central Florida, there’s no sparkling coastline or shiny amusement park to bolster Micanopy’s name. —Tara Massouleh McCay, Southern Living, 18 Dec. 2025

The presence and activities of the Russians on board these ships are of growing concern to Europe’s security services given the number of vessels in the shadow fleet sailing close to the continent’s coastlines and the potential for espionage. —Saskya Vandoorne, CNN Money, 18 Dec. 2025

The coastline where the drama unfolded. —Taylor Haught, Sacbee.com, 18 Dec. 2025

Metropolitan centers bloomed on their coastlines, and their core habitat transformed into a bustling waterway. —Kelso Harper, Scientific American, 16 Dec. 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