Where does “cuprous” come from?

Cuprous derives from Latin cuprōsus, formed with the Latin suffix -ōsus (full of, characterized by) applied to Latin cuprum (copper), ultimately from Ancient Greek κυπάρισσος (kupárissos, cypress tree) via its association with the island of Κύπρος (Kúpros, Cyprus).

cuprous (English): Of, or of the nature of, copper; Containing...