This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. Any of numerous coelenterates of the class Hydrozoa, including the freshwater hydras, hydroids, hydrocorals, and siphonophores.

adj. Of, relating to, or belonging to the class Hydrozoa.

n. Any of many colonial coelenterates, of the class Hydrozoa, including the hydras, hydroids, hydrocorals, and siphonophores.

Pertaining to the Hydrozoa; resembling the Hydrozoa, or having their characters.

n. One of the Hydrozoa, as an acaleph, medusan, or jelly-fish.

n. colonial coelenterates having the polyp phase dominant

"Turritopsis Nutricula is technically known as a hydrozoan and is the only known animal that is capable of reverting completely to its younger self."

Hydrozoa