Where does “Julius” come from?

Julius derives from Latin Iulius, from Ancient Greek ἴουλος, ultimately from Proto-Indo-European welH-, a root of uncertain meaning.

Ancestry of “Julius”, step by step

Step	Language	Word	Meaning
1	Latin	Iūlius	—
2	Latin	iuppiter	—
3	Proto-Italic	djous patēr	Jupiter
4	Proto-Italic	*djous	—
5	Proto-Indo-European	dyḗws	sky, heaven; sky god
6	Proto-Indo-European	dyéws	—
7	Proto-Indo-European	dyew-	to be bright; sky, heaven

Julius — Etymology, Origin & Word History | Etymology Explorer