strandline

• strand line

From strand +‎ line.

strandline (plural strandlines)

1. The linear mark left (on a beach etc.) by high water; (geology) the line that marks the interface between land and water; a shoreline; it changes daily, and over geologic time.
   • 2015, Steve Trewhella, Julie Hatcher, The Essential Guide to Beachcombing and the Strandline, Wild Nature Press, →ISBN, page 235:

     The beach strandline is just as much a wildlife habitat as a woodland or wildflower meadow, and every bit as diverse and interesting. It has a dynamic nature, changing every day as organic debris from the sea is deposited on the beach to be gradually broken down by the strandline inhabitants; sometimes the whole strandline is buried in sand or shingle or submerged by storm waves.