[ bak-shawr, -shohr ]
/ ˈbækˌʃɔr, -ˌʃoʊr /

noun Geology.

the zone of the shore or beach above the high-water line, acted upon only by severe storms or exceptionally high tides.
the area immediately adjacent to a sea cliff.

Origin of backshore

First recorded in 1915–20; back1 + shore1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Scientific definitions for backshore

[ băkshôr′ ]

The area of a shore that lies between the average high tide mark and the vegetation. The backshore is affected by waves only during severe storms. Compare foreshore.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.