Um·​bri·​el | \ ˈəm-brē-ˌel How to pronounce Umbriel (audio) \

Definition of Umbriel

: 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

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

First Known Use of Umbriel

1874, in the meaning defined above

Keep scrolling for more

Learn More about Umbriel

Time Traveler for Umbriel

Time Traveler

The first known use of Umbriel was in 1874

See more words from the same year

Statistics for Umbriel

Cite this Entry

“Umbriel.” Dictionary, Merriam-Webster, Accessed 29 May. 2020.

Comments on Umbriel

What made you want to look up Umbriel? Please tell us where you read or heard it (including the quote, if possible).


See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

May 2020 Words of the Day Quiz

  • a blooming wisteria tree
  • Which is a synonym of exiguous?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

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