The word derives from Old Tupi y?ara = y ("water") + ?ara ("lord; lady") = "lady of the lake" (water queen). Depending on the oral tradition and the context of the story, she can be seen either as a water nymph, a siren, or a beautiful mermaid that lives in the Amazon River.

While literal "mermaids" do not exist, the Amazon River is home to the Pink River Dolphin (Boto), which is at the center of the "Boto Encantado" legend—a myth that mirrors mermaid folklore. According to local indigenous tradition, the Boto is a shapeshifter that transforms into a handsome, well-dressed man at night to seduce and kidnap people into the mystical underwater city of Encante. In some variations, there are female versions (similar to sirens) that lure men into the depths. These legends were historically used as a cultural explanation for unexpected pregnancies or disappearances in remote river communities. In 2026, these stories remain a vital part of Amazonian heritage, often used to promote conservation of the endangered pink dolphins by instilling a sense of spiritual reverence and "taboo" against harming these semi-mythical creatures.