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

Arctic dreams Russian President Vladimir Putin has long envisioned the 3,500-mile route along Russia’s jagged Arctic coastline becoming a major artery for trade – and a driver of investment in Russian ports and oil and gas fields. — Simone McCarthy, CNN Money, 14 Aug. 2026

European observers will see the moon low in the western sky before dawn, creating dramatic opportunities to see and photograph the eclipsed moon above city skylines, coastlines and mountain landscapes as morning twilight begins. — Jamie Carter, Forbes.com, 13 Aug. 2026

Iran's semi-official Fars news agency reported Wednesday that the country's Department of Environment said oil was spotted along parts of the island's coastline. — Frank Andrews, CBS News, 13 Aug. 2026

Oman’s environment agency said on Wednesday that a vast oil spill from a leaking tanker had started to hit the country’s coastline, threatening to become one of the world’s worst in years after spreading largely unchecked for weeks. — Reuters, NBC news, 13 Aug. 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