1. A device for protection from the weather consisting of a collapsible, usually circular canopy mounted on a central rod.
a. Something shaped like an umbrella: the umbrella of a mushroom.
b. The gelatinous, rounded mass that makes up the major part of the medusa stage of most jellyfish and certain other cnidarians.
a. Something that covers or protects: The researcher's job was saved by the umbrella of academic freedom.
b. Air cover, especially during a military operation.
[Italian ombrella, from Late Latin umbrella, alteration (influenced by umbra, shade) of Latin umbella, parasol; see UMBEL.]
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