Cercarial is an adjective used to describe a specific stage in the life cycle of certain parasitic flatworms. Synonyms for cercarial include cercarian, cercarie, and cercarian stage. These terms are often used interchangeably in scientific literature to refer to the free-swimming, larval form of flatworms that infect freshwater mollusks, birds, and mammals. Other related terms include metacercaria, the encysted form of the parasite within its intermediate host, and adult fluke, the mature form of the flatworm that lives in its definitive host, such as a human or other animal. Understanding these technical terms can be helpful in studying and treating infections caused by these parasites.