Where does “torculus” come from?

torculus (Latin) comes from Latin torqueō, from Proto-Indo-European terkʷ- — to turn, spin.

Ancestry of “torculus”, step by step

Step	Language	Word	Meaning
1	Latin	torqueō	—
2	Proto-Indo-European	terkʷ-	to turn, spin

torculus — Etymology, Origin & Word History | Etymology Explorer