| An estuary is a semi-enclosed coastal body of water which has a free connection with the open sea and within which sea water mixes with fresh water. The key feature of an estuary is that it is a mixing place for sea water and a significantly-sized river to supply fresh water. |
| •owl:Thing |
| •SpatioTemporalThing |
| •Endurant |
| •PhysicalEndurant |
| •PhysicalObject |
| •NonAgentivePhysicalObject |
| •PhysicalPlace |
| •PlanetaryStructureObject |
| •GeomorphologicalUnit |
| •CoastalLandForm |
| •Estuary |