Hydronym

Hydronyms include the proper names of rivers and streams, lakes and ponds, swamps and marshes, seas and oceans.

[1] Within the onomastic classification, main types of hydronyms are (in alphabetical order): Often, a given body of water will have several entirely different names given to it by different peoples living along its shores.

Compared to most other toponyms, hydronyms are very conservative linguistically, and people who move to an area often retain the existing name of a body of water rather than rename it in their own language.

Therefore, hydronomy may be a tool used to reconstruct past cultural interactions, population movements, religious conversions, or older languages.

[14] For example, history professor Kenneth H. Jackson identified a river-name pattern against which to fit the story of the Anglo-Saxon invasion of Britain and pockets of surviving native British culture.