Decimation (Latin: decimatio; decem = "ten") was a form of Roman military discipline in which every tenth man in a group was executed by members of his cohort. The discipline was used by senior commanders in the Roman Army to punish units or large groups guilty of capital offences, such as cowardice, mutiny, desertion, and insubordination, and for pacification of rebellious legions. The word decimation is derived from Latin meaning "removal of a tenth".