The Merfolk (or Merpeople) are legendary water-dwelling human-like beings. Folklore and mythology have plenty of examples of these beings throughout the ages in various parts of the world.
Some examples could be mermaids (Sirenas in Spanish) or mermen (Tritones in Spanish), although "merfolk" could include other creatures that are not necessarily half-human and half-fish in appearance (like the Japanese kappa, the sahuagin and kuo-toa from role games or the humanoid amphibian creatures from movies like "The Shape of Water" or "The Creature from the Black Lagoon").
Etimologically "merfolk" comes from mer- 1+ folk2.
Is there a word for "merfolk" in Spanish? If so, what is it?
1. sea; marine; applied to beings that are partly sea-creatures: mercow, mermaid, merman, merswine, mersnake
2. people in general; relating to the traditional art or culture of a community or nation. (Folklore is "the knowledge of the people". In Spanish we have both forms folklore and folclore)