Definition of "medusa"

medusa

noun
plural medusas or medusae or medusæ
1. (zoology) A jellyfish; specifically, a non-polyp form of individual cnidarians, consisting of a gelatinous umbrella-shaped bell and trailing tentacles.
  Quotations
  Typically, what we think of as the jellyfish, the medusa, reproduces sexually, spawning sperm and eggs which, once fertilised, turn into sea anemone-like polyps, which attach themselves to the jellyfish’s bottom or other surfaces.
  2014, Theo Tait, ‘Water-Borne Zombies’, London Review of Books, volume 36, number 5
2. (pathology) Synonym of worm-star