Decimate means to destroy something entirely or completely annihilate it.
The verb 'decimate' originally referred to a specific Roman military punishment: the decimatio, where one in ten soldiers in a mutinous legion was executed. This mathematical precision (10%) made the word's etymology inseparable from the Latin 'decimus' (tenth). Modern usage often inflates the term to mean 'destruction of most or all,' though some dictionaries have added this looser definition as a secondary meaning. Language prescriptivists argue this represents a loss of precision, while descriptivists note that semantic drift is natural; nonetheless, the original narrow meaning remains linguistically and historically valid.