Where does “litra” come from?

litra (Medieval Latin) comes from Ancient Greek λίτρα, from Proto-Italic *līðrā — ingot.

Ancestry of “litra”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	λίτρα	litra, a Sicilian silver coin; libra, a unit of...
2	Proto-Italic	*līðrā	ingot