Where does “pásharo” come from?

pásharo (Ladino) comes from Old Spanish páxaro, from Vulgar Latin passarum, from Latin passer, from Proto-Indo-European peth₂- — to spread out; to fly.

Ancestry of “pásharo”, step by step

Step	Language	Word	Meaning
1	Old Spanish	páxaro	—
2	Vulgar Latin	passarum	genitive feminine plural of passus
3	Latin	passer	sparrow; turbot
4	Proto-Indo-European	peth₂-	to spread out; to fly

Every word from Proto-Indo-European peth₂- →Every word from Latin passer →Every word from Vulgar Latin passarum →