(noun; Latin diminutive umbra
, shade): 1. Any umbrella-shaped structure
2. The ectodermal cells located anterior to the preoral band of cilia in the development of a trochophore larva.
3. (Cnidaria: Scyphozoa) The deep to shallow bowl like body of a medusa or jellyfish; the bell
See also: exumbrella, subumbrella. 4. (Mollusca: Cephalopoda) The velum or interbrachial web interconnecting the head and arms of the finned octopods.