hydroid
/ˈhaɪdrɔɪd/
noun
- A small, simple aquatic animal related to jellyfish and corals, often growing in branching colonies attached to rocks or seaweed.
- Some hydroids have a stinging cell that can irritate human skin.
- The tide pool was full of tiny hydroids waving in the current.
- Marine biologists study hydroids to understand how colonies of animals function.
adjective
- Relating to or resembling a hydroid or the hydroid stage of certain cnidarians.
- The hydroid form of the jellyfish is a stationary polyp.
- Under the microscope, the hydroid structure looked like a tiny tree.
- The aquarium displayed a hydroid colony growing on a piece of driftwood.