Where does “Chaos” come from?

Chaos (Latin) comes from Ancient Greek χάος, from Proto-Indo-European ǵʰeh₂- — to yawn; to gape; yawn.

Ancestry of “Chaos”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	χάος	the primordial state of existence; space, air;...
2	Proto-Indo-European	ǵʰeh₂-	to yawn; to gape; yawn

Chaos — Etymology, Origin & Word History | Etymology Explorer