An indentation of the shoreline is a cove or bay.
Shoreline indentation refers to areas where a coastline curves inward, creating a bay or cove. This indentation can be caused by various factors such as erosion, tectonic activity, or volcanic processes. Indentations in the shoreline provide unique habitats for marine life and can also affect coastal erosion and sediment movement.
A 5 letter word for seashore is beach.
I think perhaps the word you are looking for is "cove".
Lumen
The indentation at the top of the manubrium is called the jugular notch.
This indentation is called the oral groove which leads to the gullet. See the link below for a diagram:
It's called an Indent, or Indentation.
A shoreline indentation is called a bay. It is a curved area of water partially surrounded by land, often less exposed to the open sea than a gulf.
It is called the suprasternal notch. And it is mine.
The Shore
Jersey Shore Soundtrack
The shore of a lake could be called:LakelandLakesideLakeshoreShoreBeachShoreline