\(\def\|{&}\)
The description of the word you requested from the astronomical dictionary is given below.
Neptune = [Latin] God of the Sea
Neptune is the eighth planet of the Solar System, counting from the Sun. Neptune is a jovian planet with a very dense and thick atmosphere (made mostly of hydrogen and helium) and many moons. Neptune has a diameter of 49,532 km and is number 5 on the list of largest objects in our Solar System.