The description of the word you requested from the astronomical dictionary is given below.
A moon of 30 km diameter at about 16,256,000 km from the planet Uranus. The gravity at its surface is about 0.0006 times as strong as on Earth. The moon goes once around its planet in about 5.4 years. The moon was discovered in 1999. Also called UXVIII (Uranus eighteen). Its provisional designation was S/1999 U3.