what is the meaning of “Coast” in law of the sea, LOSC and customary international law

“Coast” is the edge or margin of land next to the sea.

Comment
In LOAC-governed situations under the “other rules of international law” clauses in UNCLOS, a different definition may apply. The same may be the situation if the UN Charter supersedes UNCLOS or if jus cogens norms apply.
Consolidated Glossary ¶ 17 defines “coast” as the “edge or margin of land next to the sea.” Former Glossary ¶ 17 defined “coast” as “The sea-shore. The narrow strip of land in immediate contact with any body of water, including the area between high- and low water lines.”