decimation (n.) Look up decimation at Dictionary.com
mid-15c., from Late Latin decimationem (nominative decimatio), noun of action from past participle stem of Latin decimare "the removal or destruction of one-tenth," from decem "ten" (see ten). Earliest sense in English was of a tithe; punishment sense is from 1580s; transferred sense of "much destruction, severe loss" recorded from 1680s.