With thanks to Robert Macfarlane (@RobGMacfarlane)

Littoral: a shoreline region or  related to the shoreline of a sea or lake; occurring at the edge of things. It also means the zone between high and low tide marks on the shoreline. In marine biology the definition is more complex and refers to the zone and conditions of tidal currents and breaking waves. Here is a link to the Encyclopedia Britannica.