Black's Law Dictionary (2nd edition)dictionaries

Decimation

The punishing every tenth soldier by lot, for mutiny or other fa 11-ure of duty, was termed “decimatio Icgio-nis” by the Romans. Sometimes only the twentieth man was punished, (viccsitnatio,) or the hundredth, (ccntesimatio

Source: Black's Law Dictionary 2nd Ed (1910)