The description of the word you requested from the astronomical dictionary is given below.
A moon of 40 km diameter at about 49,800 km from the planet Uranus. The gravity at its surface is about 0.0008 times as strong as on Earth. The moon goes once around its planet in about 8.1 hours. The moon was discovered in 1986. Also called UVI (Uranus six). Its provisional designation was S/1986 U7.