The description of the word you requested from the astronomical dictionary is given below.
A moon of 20 km diameter at about 8,004,000 km from the planet Uranus. The gravity at its surface is about 0.0004 times as strong as on Earth. The moon goes once around its planet in about 684.2 days. The moon was discovered in 1999. Also called UXX (Uranus twenty). Its provisional designation was S/1999 U2.