The ground rent is a rent payable to the landlord of a building lease. Ground rent is also used as a general term for any long term rental that is significantly below full rental value created by the sale of a lease at a premium. (FAO. 2003. Multilingual Thesaurus on Land Tenure. CHAPTER 5. Tax and economic terms in land. https://www.fao.org/4/x2038e/x2038e09.htm)
The region of shallow waters in an estuarine or coastal marine environment which is below the level of low tide and in which the substrate is continuously submerged. (ASFA Thesaurus)