Umbrella n. : A shade, screen, or guard, carried in the hand for sheltering the person from the rays of the sun, or from rain or snow. It is formed of silk, cotton, or other fabric, extended on strips of whalebone, steel, or other elastic material, inserted, or fastened to, a rod or stick by means of pivots or hinges, in such a way as to allow of being opened and closed with ease. See Parasol.

Umbrella n. : The umbrellalike disk, or swimming bell, of a jellyfish.

Umbrella n. : Any marine tectibranchiate gastropod of the genus Umbrella, having an umbrella-shaped shell; -- called also umbrella shell.

Example:
How does an Umbrella crank work?

Taxonomy
umbrella, parasol, processions, umbraculum, China, umbrella shop, sun, collapsible, traditional umbrella, The Chinese, king, servant, Aristophanes, ribs, sunne, umbrella stand, single umbrella, umbrella makers.

Defination from the web:
umbrella or parasol (sometimes colloquially; gamp, brolly, umbrellery, or bumbershoot) is a canopy designed to protect against precipitation or sunlight. The term parasol usually refers to an item designed to protect from the sun, and umbrella refers to a device more suited to protect ...