Where does “spelaia” come from?

spelaia (Italian) comes from Italian spelare, from Italian pelo, from Latin pīlus, from Latin pīlum, from Proto-Italic pistlom, from Proto-Indo-European pis-tlo-, from Proto-Indo-European peys- — to grind, to crush.

spelaia (Italian): silk waste, taken from the filamentous burr that envelops the cocoon

Definitions

silk waste, taken from the filamentous burr that envelops the cocoon

Ancestry of “spelaia”, step by step

Step	Language	Word	Meaning
1	Italian	spelare	To remove the hair or the fur from
2	Italian	pelo	hair; surface; first-person singular present...
3	Latin	pīlus	a hair
4	Latin	pīlum	a pounder, pestle
5	Proto-Italic	pistlom	—
6	Proto-Indo-European	pis-tlo-	—
7	Proto-Indo-European	peys-	to grind, to crush

Every word from Proto-Indo-European peys- →Every word from Proto-Indo-European pis-tlo- →Every word from Proto-Italic pistlom →