The term decimate’s original definition was βto kill one in 10β. The practice was used by the Roman army in the fifth century BC as a way to inspire fear and loyalty. If any of a cohort’s soldiers acted cowardly or deserted, then lots were drawn and one unlucky soldier out of every 10 in that cohort would be killed by their own comrades. β WTF Fun Facts
Source: https://en.wikipedia.org/wiki/Decimation_(Roman_army)