Definition of "hydrozoan" []

• Any of numerous coelenterates of the class Hydrozoa, including the freshwater hydras, hydroids, hydrocorals, and siphonophores. (noun)
• Of, relating to, or belonging to the class Hydrozoa. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Turritopsis Nutricula is technically known as a hydrozoan and is the only known animal that is capable of reverting completely to its younger self."
• "Turritopsis is technically known as a 'hydrozoan' and is the only animal that is capable of reverting completely to its younger self."
• "Turritopsis nutricula, a hydrozoan, may be as close as it gets to an "immortal" creature, reverting back to its juvenile polyp stage after mating."