Where does “sielo” come from?

sielo (Ladino) comes from Old Spanish çielo, from Latin caelum, from Proto-Italic kailom, from Proto-Indo-European keh₂i-lom, from Proto-Indo-European keh₂i-.

sielo (Ladino): sky

Definitions

Ancestry of “sielo”, step by step

Step	Language	Word	Meaning
1	Old Spanish	çielo	Alternative spelling of cielo
2	Latin	caelum	heaven; sky; atmosphere, climate, weather
3	Proto-Italic	kailom	sky
4	Proto-Indo-European	keh₂i-lom	whole
5	Proto-Indo-European	keh₂i-	—

Every word from Proto-Indo-European keh₂i- →Every word from Proto-Indo-European keh₂i-lom →Every word from Proto-Italic kailom →