Where does “hiāō” come from?

hiāō (Proto-Italic) comes from Proto-Indo-European ǵʰh₁i-eh₂-, from Proto-Indo-European ǵʰeh₁y-, from Proto-Indo-European ǵʰih₁-.

Ancestry of “hiāō”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	ǵʰh₁i-eh₂-	to gape, be wide open
2	Proto-Indo-European	ǵʰeh₁y-	to yawn, gape; to gape, be wide open; to gape,...
3	Proto-Indo-European	ǵʰih₁-	—

hiāō — Etymology, Origin & Word History | Etymology Explorer