- a moon of the planet Uranus.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for umbriel
From their relative aspects in these respective positions I judge Umbriel to be about half as bright as Titania.
- one of the main satellites of Uranus
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012