Roman god of the bright sky, also a poetical name of the planet Jupiter, late 14c., from Latin Iovis, from PIE root *dyeu- "to shine," in derivatives "sky, heaven, god" (compare Zeus). In classical Latin, the compound Iuppiter replaced Old Latin Iovis as the god's name (see Jupiter). Old English had it as Iob.
variant of suffix -an (q.v.), with connective -i-. From Latin -ianus, in which the -i- originally was from the stem of the word being attached but later came to be felt as connective. In Middle English frequently it was -ien, via French.
<a href="https://www.etymonline.com/word/Jovian">Etymology of Jovian by etymonline</a>
Harper, D. (n.d.). Etymology of Jovian. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Jovian