Where does “stygius” come from?

stygius (Latin) comes from Ancient Greek στύγιος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

stygius (Latin): Alternative form of Stygius; stygian

Definitions

Alternative form of Stygius; stygian

Ancestry of “stygius”, step by step

stygius traces back through 3 separate lines of ancestry.

via Ancient Greek στύγιος

Step	Language	Word	Meaning
1	Ancient Greek	στύγιος	Stygian
2	Ancient Greek	-ῐος	belonging to; of”, “belonging to”, “pertaining to
3	Proto-Indo-European	-yós	Creates adjectives from noun or verb stems

via Ancient Greek Στύγιος

Step	Language	Word	Meaning
1	Ancient Greek	Στύγιος	relating to Styx
2	Ancient Greek	Στύξ	Styx, chief river of underworld

via Ancient Greek Στῠ́γῐος

Step	Language	Word	Meaning
1	Ancient Greek	Στῠ́γῐος	stygian

Every word from Proto-Indo-European -yós →Every word from Ancient Greek -ῐος →Every word from Ancient Greek στύγιος →