JovianPronunciation: /ˈdʒəʊvɪən/Definition of Jovian adjective 1 Roman Mythology of or like the god Jove (or Jupiter). 2relating to the planet Jupiter or the class of giant planets to which Jupiter belongs: clouds in the Jovian atmosphere the Jovian planets noun a hypothetical or fictional inhabitant of the planet Jupiter. Jovian in other Oxford dictionaries Definition of Jovian in the US English dictionary