Where does “ὀψώνιον” come from?

ὀψώνιον (Ancient Greek) comes from Ancient Greek ὀψωνέω, from Ancient Greek ὠνέομαι, from Ancient Greek ὦνος, from Proto-Indo-European wosno-, from Proto-Indo-European wesno- — price.

ὀψώνιον (Ancient Greek): salary, wages, pay, allowance; provisions