Definition: A submergent coastal landform that forms where sea levels rise relative to the land either as a result of eustatic sea level change; where the global sea levels rise or isostatic sea level change; where the land sinks. When this happens valleys which were previously at sea level become submerged.
Definition: Of plant duration, a plant whose life span extends over more than two growing seasons, c.f. annual, biennial, ephemeral, of flowering with respect to architecture, hapaxanthic, monocarpic, pleonanthic