What does "umbrella" mean?

Additional senses

1. 2.(Zoöl.) Any marine tectibranchiate gastropod of the genus Umbrella, having an umbrella-shaped shell; -- called also umbrella shell. Umbrella ant (Zoöl.), the sauba ant; -- so called because it carries bits of leaves over its back when foraging. Called also parasol ant. -- Umbrella bird (Zoöl.), a South American bird (Cephalopterus ornatus) of the family Cotingidæ. It is black, with a large handsome crest consisting of a mass of soft, glossy blue feathers curved outward at the tips. It also has a cervical plume consisting of a long, cylindrical dermal process covered with soft hairy feathers. Called also dragoon bird. -- Umbrella leaf (Bot.), an American perennial herb (Dyphylleia cymosa), having very large peltate and lobed radical leaves. -- Umbrella shell. (Zoöl.) See Umbrella, 3. -- Umbrella tree (Bot.), a kind of magnolia (M. Umbrella) with the large leaves arranged in umbrellalike clusters at the ends of the branches. It is a native of Pennsylvania, Virginia, and Kentucky. Other plants in various countries are called by this name, especially a kind of screw pine (Pandanus odoratissimus).