Hydronym

A hydronym (from Greek:ὕδωρ, hydor, "water" and ὄνομα, onoma, "name") is a proper name of a body of water. Hydronymy, a subset of toponymy or the taxonomic study of placenames, is the study of the names of bodies of water, the origins of those names and how they are transmitted through history. Hydronyms can include the names of rivers, lakes, and even oceanic elements.