Umbriel

noun

Um·​bri·​el ˈəm-brē-ˌel How to pronounce Umbriel (audio)
astronomy
: the third largest satellite of Uranus with a diameter of approximately 730 miles (1170 km)
Earlier this year, Buratti and her co-workers reported other evidence suggesting that Umbriel might be a Uranian oddity. Analyzing photographs taken through various color filters by the Voyager 2 spacecraft, they found that the ratio of green light to violet light varies widely over Umbriel's surface.—Science News, 16 Nov. 1991

Word History

First Known Use

1874, in the meaning defined above

Time Traveler
The first known use of Umbriel was in 1874

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

  1. Expanded definitions
  2. Detailed etymologies
  3. Advanced search tools
  4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now

Browse Nearby Words

Umbridae
Umbriel
umbriferous
See all Nearby Words

Cite this Entry

“Umbriel.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Umbriel. Accessed 8 Jul. 2026.

Copy Citation
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of gambol

See Definitions and Examples »

Popular in Grammar & Usage

See More

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)
See More

Popular in Wordplay

See More

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

One-Word Oxymorons: Bittersweet, Spendthrift, and More

Ten Words Ending with a Silent ‘T’

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

Is that lie 'bald-faced' or 'bold-faced'?

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
hangman letters and game
Hangman Lightning Round Figure out which word fits in the blanks.
See All