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 professors were criticized for their reactionary views, but they were protected under 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.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.