The story
From Ancient Greek Σειρήν (Seirḗn, “Siren from Greek mythology”) + μέλος (mélos, “limb”) + -εια (-eia, nominal suffix).
Etymology from Wiktionary, CC BY-SA 4.0.
sirenomelia
Today it means: A rare congenital deformity in which the legs are fused together, giving them the appearance of a mermaid's tail. Full definition →