The Order Actinaria is a taxonomic classification within the phylum Cnidaria that includes all species of sea anemones. If you are writing about this group of organisms, it might be helpful to know some synonyms or alternative names that can be used. These might include the subclass Zoantharia, which was once used to refer to all cnidarians with a polyp stage, but is now considered outdated. Another alternative is Anthozoa, which is a broader classification that includes all cnidarians with a polyp stage, including sea anemones, corals, and gorgonians. Knowing these synonyms can help ensure accurate communication and classification of these fascinating and diverse marine creatures.