noun
- marine animals belonging to the class Hydrozoa, including jellyfish, hydroids, and siphonophores
Usage: biology; zoology
Examples
- Hydrozoans are found in oceans worldwide.
- The Portuguese man o’ war is one of the most dangerous hydrozoans.
- Marine biologists study hydrozoans to understand cnidarian evolution.
- Many hydrozoans have both polyp and medusa stages in their life cycle.
- Some hydrozoans form colonies that can span several meters.
- The stinging cells of hydrozoans help them capture prey.