The littoral zone is the part of a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. It always includes this intertidal zone and is often used to mean the same as the intertidal zone. However, the meaning of "littoral zone" can extend well beyond the intertidal zone.
There is no single definition. What is regarded as the full extent of
the littoral zone, and the way the littoral zone is divided into
subregions, varies in different contexts (lakes and rivers have their
own definitions). The use of the term also varies from one part of the
world to another, and between different disciplines. For example,
military commanders speak of the littoral in ways that are quite
different from marine biologists.