From MarineSpecies Traits Wiki
Definition of a Sea-dike:
An artificial earthen wall, often meant to prevent flooding of the hinterland.Like revetments
but without, or hardly any, beach in front of the structure.
This is the common definition for a Sea-dike, other definitions can be discussed in the article
The former Hondsbossche and Pettemer sea defence in the Netherlands
sea dike near Westkapelle (the Netherlands)