RhymeZone: nectocalyx definitions

Definitions of nectocalyx:

noun: (zoology) The swimming bell or umbrella of a jellyfish or medusa.
noun: (zoology) One of the zooids of certain Siphonophorae, having somewhat the form, and the essential structure, of the bell of a jellyfish, and acting as a swimming organ.

(Definitions from Wiktionary)