Jellyfish n. : Any one of the acalephs, esp. one of the larger species, having a jellylike appearance. See Medusa.

Example:
What does a Jellyfish and coral have in common and how are they both different?

Taxonomy
jellyfish, species, polyp, jellyfish stings, stings, blooms, tentacles, gene, humans, cells, body, jellyfish species, jellies, populations, scientists, GFP, Suborder, hydromedusae.

Defination from the web:
... Jellyfish (also known as jellies or sea jellies) are free-swimming members of the phylum Cnidaria. ...