The description of the word you requested from the astronomical dictionary is given below.
A moon of 82 km diameter at about 50,080 km from the planet Neptune. The gravity at its surface is about 0.0015 times as strong as on Earth. The moon goes once around its planet in about 7.5 hours. The moon was discovered in 1989. Also called NIV (Neptune four). Its provisional designation was S/1989 N5.