Here's why:
* Headland: A headland is a piece of land that juts out into the sea. It's a high point of land that sticks out from the coastline.
* Bay or Cove: These are indentations or curved sections of the coastline that are surrounded by land on three sides. They are the opposite of headlands as they are recessed areas of the coastline, rather than protruding ones.
Other terms that could be considered opposites of headland, depending on the context, include:
* Beach
* Shoreline
* Inlet
Let me know if you have any other questions!