sellő

Etymology
Originally referred to a quick, turbulent section of a river. This latter meaning could come from the present participle of a hypothetical verb serlik, with rl assimilating into ll. The root ser is an onomatopoeia for fast movement or rotation and can be found in sarj, sarkall, sarkantyú, sarok, serdül, serény, serken, sőre, surján, sürget, sürög, sűrű and szorgalom.

Noun

 * 1) mermaid mythological woman with a fish's tail