adjective
Definition: Relating to a group of small, mostly marine animals that are part of the class Hydrozoa, which includes jellyfish and corals.
Example: The hydrozoan species can be found in both freshwater and saltwater environments.
noun
Definition: A type of small sea creature that belongs to a group of animals called coelenterates, which includes both solitary and colonial forms, such as hydras and jellyfish.
Example: The hydrozoan is often found in both freshwater and marine environments.