Cnidarians are a diverse group of animals that exhibit a wide range of different physical and biological traits. Some common synonyms for this group include Coelenterates, which refers to their unique body structure, as well as jellyfish, sea anemones, and hydrozoans. These synonyms often describe specific sub-groups within the larger category of Cnidarians. For example, jellyfish are often used to refer to the class Scyphozoan, while sea anemones and hydrozoans are typically found within the class Anthozoa. Overall, these synonyms help to communicate the rich diversity of Cnidarians, which are found in a wide range of aquatic environments around the world.