um·​bra | \ ˈəm-brə How to pronounce umbra (audio) \
plural umbras or umbrae\ ˈəm-​(ˌ)brē How to pronounce umbra (audio) , -​ˌbrī \

Definition of umbra

1a : a conical shadow excluding all light from a given source specifically : the conical part of the shadow of a celestial body excluding all light from the primary source
b : the central dark part of a sunspot
2 : a shaded area

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Other Words from umbra

umbral \ ˈəm-​brəl How to pronounce umbra (audio) \ adjective

Did You Know?

The Latin word umbra ("shade, shadow") has given English a range of words in addition to "umbra" itself. An umbrella can provide us with shade from the sun. So can an umbrageous tree. (In this case, umbrageous means "affording shade.") The connection to shade or shadow in other "umbra" words is less obvious. When we say someone takes "umbrage," we mean they take offense, but in times past people used the word as a synonym of "shade" or "shadow." The two senses of "umbrage" influenced "umbrageous," which can mean "inclined to take offense easily" as well as "affording shade."

Examples of umbra in a Sentence

strange noises were coming from the wooded umbra beyond our campfire during a solar eclipse observers located within the umbra experience a complete blocking of the sun by the moon
Recent Examples on the Web But, unlike a normal full moon that reflects the sun’s illumination, during a lunar eclipse the moon emanates the Earth’s shadow (known as the umbra). Aliza Kelly Faragher, Allure, "Your Guide to Lunar & Solar Eclipses in 2021 and How They’ll Affect Your Life," 23 Dec. 2020 Both partial and total lunar eclipses occur when the moon passes through part or all of the umbra, the main part of our planet's shadow. Doyle Rice, USA TODAY, "A 'penumbral' lunar eclipse is coming this weekend. What does this mean?," 30 June 2020 During total lunar eclipses, the entire moon is engulfed in the darkest part of the planet’s shadow, called the umbra, which can turn the silvery orb a ruddy orange or even a deep blood red. Andrew Fazekas, National Geographic, "See a lunar eclipse on the Apollo 11 launch anniversary," 16 July 2019 The penumbra is the partial outer shadow, and the umbra is the full, dark shadow. Ashley Strickland, CNN, "Much of the world will be able to see a partial lunar eclipse Tuesday -- just not the US," 16 July 2019 Because of the low sun angle, the umbra will be longer. The Washington Post, The Mercury News, "A 6,000-mile path will experience a total solar eclipse next week. The display won’t be easy to see.," 26 June 2019 The full eclipse will begin at 11:41 p.m. and last for just over an hour, until 12:43 a.m. This will be the best viewing time, when the moon is in the umbra, or the full shadow the Earth. Jill Kiedaisch, Popular Mechanics, "How a Total Lunar Eclipse Works," 18 Jan. 2019 The moon will have finished its traversing of the Earth’s shadow, or umbra. Brian Resnick, Vox, "The longest lunar eclipse of the century will be on July 27," 24 July 2018 But, unlike a normal full moon that reflects the sun’s illumination, during a lunar eclipse, the moon emanates the Earth’s shadow (known as the umbra). Aliza Kelly Faragher, Allure, "A Beginner's Guide to Eclipses in 2018 and How They Can Affect Your Life," 16 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'umbra.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of umbra

1638, in the meaning defined at sense 2

History and Etymology for umbra


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Time Traveler for umbra

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The first known use of umbra was in 1638

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Last Updated

27 Dec 2020

Cite this Entry

“Umbra.” Dictionary, Merriam-Webster, Accessed 24 Jan. 2021.

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More from Merriam-Webster on umbra

Thesaurus: All synonyms and antonyms for umbra

Britannica English: Translation of umbra for Arabic Speakers Encyclopedia article about umbra

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