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coastline

American  
[kohst-lahyn] / ˈkoʊstˌlaɪn /

noun

  1. the outline or contour of a coast; shoreline.

  2. the land and water lying adjacent to a shoreline.

coastline British  
/ ˈkəʊstˌlaɪn /

noun

  1. the outline of a coast, esp when seen from the sea, or the land adjacent to it

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of coastline

First recorded in 1855–60; coast + line 1

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.