The description of the word you requested from the astronomical dictionary is given below.
Saturn; Saturnus = [Latin] father of Jupiter
Saturn is the sixth planet of the Solar System, counting from the Sun. Saturn is a jovian planet with a very dense and thick atmosphere (made mostly of hydrogen and helium), many moons, and wide rings. Saturn has an equatorial diameter of 120,536 km and is number 3 on the list of largest objects in our Solar System.