Where does “oscillate” come from?

Oscillate derives from Latin oscillatus, past participle of oscillō, from oscillum (a small mask or weight hung in windows), from ob- combined with obolus, from Ancient Greek ὀβολός, from ὀβελός (spit or pointed object), from βέλος (projectile or missile).

oscillate (English): To swing back and forth, especially if with a...